UMAYYAD BUILDING TECHNIQUES AND THE MERGING OF ROMAN-BYZANTINE AND PARTHO-SASSANIAN TRADITIONS: CONTINUITY AND CHANGE

UMAYYAD BUILDING TECHNIQUES AND THE MERGING OF ROMAN-BYZANTINE AND PARTHO-SASSANIAN TRADITIONS: CONTINUITY AND CHANGE Ignacio Arce Abstract This paper analyses the introduction, merging and use of building materials and techniques, architectural typologies and urban patterns, during the Umayyad period in Bilad al-Sham (present day Syria, Palestine and Jordan), within the general framework of the cultural interchange that took place in that period between eastern and western traditions. For most of its history, and especially in Antiquity, this was a frontier area, or a buffer zone in modern terms, between the main regional powers: Egypt and the successive Mesopotamian empires; Persia and Greece; the Seleucid and Ptolemaic kingdoms; Rome and Parthia; Byzantium and the Sassanians. As a result, it not only witnessed war, invasion and destruction, but also fruitful economic and cultural interchange. This frontier was lifted twice: first, during the reign of Alexander, and, secondly with the rise of Islam. Introduction After a military campaign launched against the Emperor Phocas in A.D. 607, the Sassanians over-ran the Limes Arabicus in 611 and ravaged the north of Syria. In 614, they captured Palestine and Jerusalem, carrying off the Holy Cross as war booty to their capital, Ctesiphon. Shortly after, they captured Egypt. It took the newly-proclaimed emperor, Heraclius, until 622 to react and raise an army to recover these lost but vital territories. He reached the heart of the Sassanian Empire in 628, from which he brought back the plundered relics, and regained Jerusalem two years later. The weakening of the eastern frontier had started a century earlier when, during the reign of Justinian, the army abandoned the fortifications built along the Limes Arabicus. In their place, local, Christianised L. Lavan, E. Zanini, and A. Sarantis (edd.) Technology in Transition A.D. 300–650 (Late Antique Archaeology 4 – 2006) (Leiden 2007), pp. 491–537 LAVAN, LAA4_F23-491-537.indd 491 1/11/2008 6:09:39 PM 492 ignacio arce Arab tribes—at first the Banu Salih and, afterwards, the Ghassanids—were entrusted with its defence, of the Limes Arabicus, as foederati of Byzantium.1 The subsequent long-lasting wars, religious conflicts and political crises induced instability and general unrest in Late Roman Syria, which was worsened under the despotic reign of Phocas and would never be fully resolved. For these reasons, Islamic expansion encountered almost no resistance; Byzantium was still weak, even after regaining the territories lost to the Persians, whilst the defeated Sassanian kingdom had barely survived. The fate of Bilad al-Sham was sealed in A.D. 636 at Yarmuk. Mesopotamia and Persia surrendered after the battle of Qadisiyyah in 636. The final defeat of the Sassanian kingdom followed a few years later, in 642, at Nahawand near Merv. The last Shah, Yezdigird III, was assassinated in 651. Thus, following the Arab conquests, the frontier between the two ‘superpowers’ of the antique Middle East, between the East and the West, ceased to exist. The area now became the centre and capital of the new Umayyad power for about a century. Byzantium would recover and become the sole power opposing the advance of Islam in Anatolia, whilst the Sassanian Empire disappeared forever. This political and military context helps us to understand the success of the emergent Muslim power under the first ‘orthodox’ and, subsequent, Umayyad, Caliphs, and the references and models adopted and developed by their new culture thereafter. As I will discuss below, these affected all aspects of the cultural life of this new society, in particular, the development of architecture and urbanism. A New Image of Power Throughout history, rising powers have caused the downfall of other consolidated, highly-developed empires. They have subsequently imitated, adapted and transformed the pre-existing cultures of their predecessors. The new Umayyad Caliphate had both the Byzantine and the Sassanian empires to draw upon; an ambiguous situation that would eventually create political and administrative confusion in, for instance, the bureaucratic system: in Syria, Greek was the official language, while 1 Similarly, the Sassanians relied on the Lakhmids for the defence of their desert frontier. LAVAN, LAA4_F23-491-537.indd 492 1/11/2008 6:09:42 PM umayyad building techniques 493 in Persia and Mesopotamia, Farsi (Palhevi) prevailed. Similarly, both of the pre-existing monetary systems were maintained, posing a genuine threat to the political and economic authority of the new state. This chaotic situation was worsened by the difficult struggle the Umayyads faced to establish their control over the Caliphate. They were only able to fully secure their power under the reign of Marwan I, founder of the marwanid branch of the Umayyad family, who is known to have replaced, not without protest, the electoral system of the Caliphate with a hereditary one. His son, Abd el-Malik, introduced further reforms that ensured the economic and administrative control of the new State, and produced the required political stability: he unified the administration, promoted Arabic as the official language of the public court, or Diwan, and reformed the monetary system, which would soon become the standard system in the Mediterranean basin. Moreover, he acknowledged the importance of architecture and urban planning in creating symbolic supremacy and effective control over the newlyconquered territories. In fact, the building of new cities had already started with the first conquests: Caliph Omar, who is considered by many to be the real father of the Islamic state, had founded strategic sites at Basra, Kufa (in Iraq), and Fustat (in Egypt). In contrast to the Byzantines and the Sassanians, the Umayyads still lacked well-defined protocols for ceremonial occasions, and symbols of power. The need for a protocol of display and the availability of the two preceding models presented a difficult choice. The Sassanian tradition was more suitable for re-use, given that it had been released from its political meaning and symbolic associations, belonging as it did to a vanquished kingdom.2 In contrast, Roman elements would prove to be far harder to incorporate as, although weakened, the Roman Empire was the surviving power still opposing the Umayyads. Therefore, the Umayyads erected aulic and representative buildings to rival the symbolic, fascinating and magnificent Christian churches, and other similar Roman monuments in the region, the monumentality 2 As part of that pragmatic approach mentioned above, old forms and spaces were eagerly re-used by the new rulers, although they were sometimes modified. For instance, even though the Umayyad decoration of arches clearly originated in Sassanian custom, highly symbolic elements, such as the crescent at the apex of the arch, and the hairknot with the royal scarf at the springing line, have disappeared. See Arce (2001a) and (2001b). LAVAN, LAA4_F23-491-537.indd 493 1/11/2008 6:09:42 PM 494 ignacio arce and number of which were constant reminders of the power of the surviving Byzantine tradition. Since a swift and effective reaction was required, the Umayyads solved their problem in a very pragmatic way: they began to merge the cultural traditions of the vanquished empires, optimising existing resources, and mixing typologies, forms, materials and techniques. Thus, they created an entirely new culture including, in particular, an innovative architecture that was completely different from its predecessors, and had a strong and vigorous identity. Adoption of Urban and Architectural Typologies The swiftness of the Arabs’ conquest and their need for territorial control, meant that they required simple and efficient urban layouts. The new Umayyad rulers realised that towns were essential to their policy of territorial control, especially in light of the fact that their markets played a vital role in the monetary economy of the new state.3 These factors re-affirm the idea that ‘urban culture’ was not only maintained, but enhanced under the new Islamic rulers. Further, the former view that the new power neglected declining classical cities has been contradicted by archaeological evidence for the Arabs’ active and planned transformation of these cities to meet new economic and commercial demands, as well as the creation of many new cities. Many of these new cities were initially established as military encampments: the so-called amsar (singular misr), or encampment-towns, created ex-novo, were essential for the urban and territorial strategy. Their layout was based on various models, whatever their cultural origin. The best known examples, located in the former Roman provinces of Syria and Palestine, resembled the rectangular Roman military camp. These include Anjar in Lebanon and Aqaba in Transjordan.4 Others copied the model of the Partho-Sassanian circular towns; this might have been the case for amsar in Iraq and Persia, such as Basra 3 Some of the religious prescriptions of Islam reinforced the role of cities in the new state, like the need for the entire male population of a city and its surroundings to congregate for the Friday prayers. On this occasion, administrative edicts were proclaimed and read together with the religious sermon during the Khutba, or sermon (reflective of the unity between politics and religion in Islam, where praying was conducted by the Caliph or his deputy). 4 For Anjar, see Chehab (1953), for Aqaba, see Whitcomb (1998). LAVAN, LAA4_F23-491-537.indd 494 1/11/2008 6:09:42 PM umayyad building techniques 495 and Kufa, although we mainly know about these cities from literary sources. Later examples of cities built on a circular plan include the Abbasid foundations of Baghdad and Heraqlah.5 Among the Sassanian towns that would have served as models are Ctesiphon, Hatra, Harran, Darabjerd and Firuzabad. One can even trace earlier antecedents of this pattern, always in the Mesopotamian-Persian region, such as Sinjerli (from the Hittite period), or Sagbat/Hagmatana (founded in 700 B.C. by Median kings). The plans of other cities, such as the palatine city at the Amman citadel, created on an existing town (ex-novo, but not exnihilo), were influenced by both Hellenistic and Central-Asian models. On the one hand, we can identify a pragmatic strategy of re-using pre-existing structures and regularising the resulting open spaces (in our case, the souq, or market square) by means of porticoed structures (similar to the Hellenistic models of the agorae of Assos and Athens). On the other hand, the pattern of segregating the Palace itself from both the palatine city (both on a hill) and the lower city populated by commoners, is reminiscent of central Asian cities.6 A similarly pragmatic approach is noticeable in building typology. The Umayyads favoured models that could easily be adapted to different purposes, rather than spatial configurations clearly serving a single function. Buildings serving very specific purposes, such as throne halls, mosques or baths, were the exceptions. The Umayyad builders also alternated between Roman and Sassanian models in their construction of palaces and other religious and symbolic buildings. For instance, a three-aisled basilica in Mshatta ends in a Late Roman triconch hall, while at Amman and Kufa, the typical domed Sassanian throne hall can be found. This was preceded by an iwan opening into a courtyard. This confused alternation of extant models of symbolic protocol (and, in some cases, their co-existence) would eventually contribute to a new ‘oriental’ model. The Dome of the Rock, built on top of the remains of the Jewish Temple at Jerusalem (abandoned after its destruction by Titus, and never rebuilt by the Christians, in order to fulfil the Prophecy), is extremely significant; it illustrates to what extent magnificent and symbolic buildings in key locations contributed to the spiritual and symbolic take-over of the territory. Its erection was the most important expression of Islamic 5 6 Creswell (1989) figs. 137 and 171. Arce (2000). LAVAN, LAA4_F23-491-537.indd 495 1/11/2008 6:09:42 PM 496 ignacio arce political and religious ambitions; a truly propagandistic act by which the new rulers and the new religion proclaimed their link to the lineage and faith of Abraham. Moreover, it was intended as a defiant message to the Christians regarding the actual meaning of the Prophecies: its inscription reproached them for their ‘polytheistic deviation’ (their faith in the Holy Trinity), and embodied an invitation to conversion.7 Something similar can be said regarding the great mosque at the new political capital, Damascus, which was built on the premises of the former Christian Cathedral. Both structures, in particular, the Dome of the Rock, are regarded as ‘Late Roman’ by many art historians due to the architectural typology and building techniques used, although some of the mosaic patterns display traces of Sassanian influence. It seems that the very limited use of oriental models in these buildings should be explained by their very early date of construction (during the reign of Abd el Malik), and geographical location within the former Roman provinces of Palestine and Syria. At this stage, the artisans in these provinces would have been Syrians with a classical background. The first steps towards a real merging of oriental architectural models and techniques did not take place for another decade. The Mosque represents a clear example of the creation of a new kind of building, which initially portrayed two different styles, again influenced by distinct antecedents. Their adaptation was unquestionably influenced by the activities that took place within them: a mosque was mainly intended for Friday prayer, and as a meeting room for the entire male population of a town and its surroundings. The ‘Syrian’ mosque was derived from the Christian basilica, its prayer hall, or haram, constituting a ‘linear’ space defined by parallel porticoes. The porticoes (in churches, there were usually two that defined three aisles along the axis of the building) were usually turned transversally, so that they were aligned with the Quibla wall.8 This wall 7 Grabar (1959). The layout of the porticoes in Bilad al-Sham could be related to the re-use of churches. The direction of prayer was then shifted 90 degrees: from the East, as was customary for Christians, to the South (towards Mecca) for the Muslims. When mosques, e.g., those at Cordoba, or Mértola in Portugal, were turned into churches, the opposite happened. In most cases, the mihrab needed to be blocked and concealed, or transformed into a secondary chapel, and a new apse introduced in the east wall:— Ewert (1973). This also explains why the Cathedral of Sevilla, built on the premises of the former Congregational Mosque, lacks the directional spatial sense of a standard Gothic church. 8 LAVAN, LAA4_F23-491-537.indd 496 1/11/2008 6:09:42 PM umayyad building techniques 497 was always orientated towards Mecca, and included (from the 8th c. onwards) the mihrab—another alien adoption, although its Jewish or Christian origin is still debated—which the congregation faced during prayer. The number of aisles in a ‘Syrian’ mosque could vary from three to five, or even more. In front of the haram, there was a courtyard or sahn, possibly related to the Christian atrium, with a surrounding portico. Damascus is a typical large-scale illustration, while those at Al-Walid, or Hallabat in Jordan, represent more modest examples. The latter were in fact so small that they possessed no courtyard, although Hallabat possessed an external portico, which clearly drew heavily upon Christian architectural models.9 A second type of mosque imitated the Persian apadana; a square hall with no clear directional orientation that was usually covered by a ‘forest of columns’. In such spaces, supports were placed at regular intervals and carried lintels or arches, usually in both directions. Some of these columns were sometimes eventually removed to shed more light on the inner space, creating a sort of courtyard. Unsurprisingly, almost all examples of this type are found in Persia and Mesopotamia: for instance, Kufa, Tarik Khana (Damghan), and Susa in Khuzistan. The Amman Citadel Mosque is an outstanding example of this kind of ‘Persian’ Mosque, found un-expectedly in Bilad al-Sham.10 In the subsequent stage, this distinction between ‘basilica’ and ‘apadana’ mosques became confused and new kinds emerged that were a mixture of these types and even incorporated new features. The interesting thing about Umayyad architecture is that its influences can be clearly identified, thereby allowing the study of its transformation. In later times, these styles were again merged with other influences, so that they became more diffuse and harder to trace. In the case of hammams (bath buildings), the merging of traditions is more visible in building techniques than in typology. In the Early Islamic world, the standard Roman-Byzantine plan was adapted with little change: only the apodyterium was replaced by a reception hall.11 This highly standardised design may imply the presence of ‘drawn’ models or plans, executed in different places, with different materials 9 10 11 Arce (2004) in press. Arce (2000). See Arce (2004). LAVAN, LAA4_F23-491-537.indd 497 1/11/2008 6:09:42 PM 498 ignacio arce and techniques, according to the resources available. For instance, the baths of Hammam As-Sarraj and Qusayr ‘Amra, (both in Jordan) were almost identical in plan and elevation, but were erected using different techniques: Sarraj with finely-cut limestone ashlars of the ‘Late Roman’ tradition (probably due to its location very close to the quarries), and Amra with rough masonry held together by gypsum-lime mortar, a technique of Sassanian origin, which was also used at nearby Qasr Harane. From Merging to Hybridisation In the next step of this process, it is possible to observe the combination of different techniques and typologies in a single building style. It might be argued that this resulted from a situation in which a conscripted workforce of artisans and technicians, from all four corners of the empire, worked on the construction of a great number of buildings in a very short period of time;12 part of a deliberate and planned attempt to create an original and different architecture for the new state.13 Therefore, the true hybridisation of technical and artistic influences was inevitable. Architectural and spatial archetypes from one tradition were built with techniques, and decorated with patterns and elements from another, and vice-versa. Qasr Harane is a good example of this stylistic interaction. In this case, the typical Syrian bayt (a spatial unit composed of a central and elongated hall flanked on both sides by two small chambers which opened onto it) featured as the main element of the compositional plan. This was covered with diaphragm arches (common to Syrian and Parthian traditions), but built with Sassanian techniques (fig. 9), involving the use of squinches, pre-cast gypsum, structural elements and gypsum mortar. The structure is decorated with gypsum-made pre-cast niches that were composed of paired colonnettes, 12 At one point, the building ‘fever’ of the Umayyads actually jeopardized the finances of the state. The last Umayyad Caliph was finally obliged to give up all building activities under the weight of increasing criticism. 13 It resembles the ‘melting pot’ of workers involved in the construction of the Palace of Darius at Susa where, according to its famous inscription, the Babylonians made adobe and bricks, the stonecutters from Sardles and Jionia were responsible for the stone masonry, and gold decoration was applied to the walls by workers from Egypt and Media. LAVAN, LAA4_F23-491-537.indd 498 1/11/2008 6:09:43 PM umayyad building techniques 499 horse-shoe arches, and dog-teeth cornices. It is easy to understand why some scholars have regarded this amazing building as a Sassanian structure built during the occupation of A.D. 614–30. The process became increasingly complex, especially where decoration was concerned. For example, the same ‘Sassanian’ decorative elements that were traditionally modelled, or cast, in gypsum at Harane, were carved in stone at Qastal and Amman (see below fig. 6). A further level of complexity was achieved at Khirbat Al-Mafjar (near Jericho), where stone-carved Umayyad versions of the gypsum-made ‘Corinthian’ capitals of the Partho-Sassanian world were found. It is remarkable that the choice was made to reproduce in stone the oriental version with its singular shape, along with details adapted to the gypsum material, instead of the original stone-carved model. The cross-fertilisation of eastern and western techniques and typologies actually started before the Umayyad period. The disappearance of the frontier only re-activated and accelerated the natural and continuous process of exchange between neighbouring cultures. This process had gained momentum during the Hellenistic period (mainly in the Greek colonies of Mesopotamia and Persia), when this frontier had ceased to exist. Continuous cultural intercourse between the East and the West provoked the transformation of original features, sometimes with unexpected but highly original results. One of the inherited traditions involved the application of decorative features in carved stucco to a stone or brick core. This technique, apparently Mesopotamian in origin, and developed in that region during the Hellenistic period, was adopted by the Parthians, and afterwards, by the Sassanians. Although it was used extensively, and, during the Early Islamic period, was improved by artisans coming from Persia and Mesopotamia, it had already been introduced into the Levant from the East before the Umayyad era, during the Hellenistic and Nabatean periods, through the Parthian influence on Nabatean culture. The origins of this technique can be traced back to the arrival of the Greek colonialists in Persia and Mesopotamia after the conquests of Alexander. These new arrivals were confronted with an architectural tradition consisting of brick and cobble masonry, bound by gypsum mortar and lined with stucco. This forced them to adjust classical decorative and architectural features to the available material, carving or stamping them in gypsum. The resulting, hybrid decoration was adopted by the Parthians, who also introduced new Roman influences, and then eventually carried it back to the Levant—and in particular to the Nabatean Kingdom—along trade routes. Examples LAVAN, LAA4_F23-491-537.indd 499 1/11/2008 6:09:43 PM 500 ignacio arce can be found in column shafts and capitals from various buildings at Petra—for example, Ed-Deir, Qasr el-Bint—or those from the Herodian palace at Machaerus (fig. 1). The capitals of the congregational mosque at the Citadel of Amman (fig. 1) can, therefore, be seen as the outcome of a long process of hybridisation; the core of the column shafts and capitals consisted of carved limestone, thereby adhering to western techniques, and not the rubble masonry that was prominent in the Sassanian antecedents, or in the co-eval buildings of the Amman citadel palace itself. The decoration was executed in carved gypsum stucco of Partho-Sassanian origin, which was applied to the structural core, while the column shape and general plan of the building were also of Persian origin. The decision to use a ‘Byzantine’ stone-carved core in these columns resulted from the need for a more reliable support for the roof, which covered the ‘forest of columns’.14 This technique could have allowed the application of the decoration to the columns through the carving of patterns directly onto the stone itself (as was done, for instance, inside the Vestibule—see below), or into its own external façade.15 However, in this case, it seems that the builders adopted this quicker and cheaper solution for the interior, having probably been constrained by the limited resources available. Even so, their pragmatic and utilitarian approach led them to carve decorations into the stone in areas where the adherence of the stucco could not be guaranteed, for instance, in the downward-facing lower part of the capital. The relationship between the load-bearing structure and decoration of a building is one of the key differences between classical and Persian architecture. The close relationship and high degree of articulation between structure and decoration in Greco-Roman architecture can be explained by the ‘structural’ origin of its decorative elements: most features of the earliest edifices—in the first place, in temples—gradually lost their structural raison d’être and evolved into purely ornamental elements, but their display remained closely related to the original structural elements. This generated very strict syntactic rules (the Classical Orders), which prescribed the use and location of the decorative vocabulary. Thus, the Classical Orders define the use and meaning of the classical architectural language as a whole 14 15 Arce (2002). Ibid. LAVAN, LAA4_F23-491-537.indd 500 1/11/2008 6:09:43 PM umayyad building techniques 501 Fig. 1 Translation of shapes and techniques. a: Khirbat al-Mafjar. Bath Porch. Stone-carved ‘Corinthian’ capital. This capital imitates the features of the gypsum-carved Sassanian version of the classical model; b: Machaereus ( Jordan). Herodian fortress. Ionic capital, with decorative features applied in stucco onto a stone core; c: Amman Citadel. Capital carved into stone imitating Sassanian models carved in stucco; d: Amman Citadel Mosque. Capital. Restoration carried out by the author based on the remains found in situ. The decoration in carved stucco was applied onto the stone core, except the lower part of the capital (facing down) that was carved on the stone core itself. A classical building can, therefore, be called a ‘structure’ in two ways: it is both a ‘construction’—from the Latin struere, to build—and a “complex configuration of elements, closely inter-related by fixed rules”, according to the additional modern meaning of the term in linguistics. In contrast, in Partho-Sassanian architecture—and in Mesopotamian and Iranian architecture in general—there is a clear dichotomy between structural and decorative elements, as they were neither clearly articulated nor related from the start. Apparently, the lack of resources available in Mesopotamia led to poorly-built, load-bearing structures,16 16 Information on Sassanian architecture and building techniques is very rare; on one hand, only a small number of ruins are preserved. This is partly due to the disappearance of the Sassanian Kingdom and the replacement of its culture by the Islamic one, and partly to the poor quality of Sassanian construction work. On the other hand, LAVAN, LAA4_F23-491-537.indd 501 1/11/2008 6:09:43 PM 502 ignacio arce put together from earth, or gypsum, and stones, bricks or adobe. The decorative features faced the same technical constraints, and consisted of mud, and later, of gypsum-made plasters and renderings.17 It was devised as a skin, coating, protecting and concealing the load-bearing structure, rather than enhancing its tectonic features. The most characteristic decoration resulted from the quick covering of extended surfaces with repetitive motifs, using stamps and moulds. This technique would give birth to the ‘infinite developing patterns’ that were essential in later non-figurative Islamic art.18 Iranian architecture was also characterised by the use of timber, which was mainly brought from the mountainous and wooded areas in the north, near the Caspian Sea. The linear elements, which were characteristic of timber constructions, clearly influenced the ‘forests of columns’ of the apadanas, or the ‘lintelled squinches’, and may also have had an impact on the shape of some other Umayyad decorative forms of Sassanian origin, such as corbels, and coffered ceilings. The different relationships between structure and decoration in western and eastern building and architectural traditions, were ‘subverted’ and blurred by the Umayyads in their combination of materials and formal repertoires from both cultures. Apart from the examples of the decorated capitals, mentioned above, there are other outstanding examples of this intercourse, which sometimes affected the relationship between decoration and structure. For instance, in the Amman Citadel Vestibule, both concepts are apparent in the same building, even though they contributed to the same decorative feature: the Sassanian niches that are capped with horse-shoe arches, supported by paired colonnetes and decorated with dog-teeth. Here, these niches were carved into stone (not like at Harane, where they were still modelled and cast in there have been few studies conducted in situ, and only a very small amount of material is available to foreigners, especially after the 1979 revolution. 17 Other examples of surface wall decoration following the same ‘oriental’ concept, are the Sumerian mosaics with decorative pottery cones, embedded in the walls, for example, those at Warka–Frankfort 1970: figs. 8 and 9. 18 The role of textiles must also be mentioned, in the later development and success of these decorative concepts and patterns in Islamic art. This parallel influence derives from Centro-Asiatic nomadic populations, who constructed shelters by covering wooden frames with furs and printed or woven cloths (the yurt of the Turkmen and Mongol tribes is the best known example). While these shelters present a clear distinction between load-bearing structures and their protective ‘skin’, the patterns used on these textiles for centuries influenced the applied arts and mural paintings in the region between central Asia and Mesopotamia. LAVAN, LAA4_F23-491-537.indd 502 1/11/2008 6:09:44 PM umayyad building techniques 503 gypsum) in two different ways in different parts of the structure. First, they are present in the long friezes running at the base and on the top of the building and, second, cover a large surface panel in between these friezes. In the former case, the translation of this feature into stone also implies a conceptual change in its execution and display; it is no longer a decorative pattern, carved all over the surface. In contrast, in the latter case, it was carved over the wall masonry base with no regard for its joints, and was consequently closer to Sassanian styles. Instead, it is restricted and related to the elements on which it was carved: each element of the niche (the paired colonnetes, the capping arches, and the back panels) actually having been carved onto a unique ashlar, and built and interlocked into the masonry fabric. This practice adhered more closely to the ‘classical tradition’ (see fig. 6). Therefore, it is clear from such instances that Umayyad architecture was a multi-coloured fusion of oriental and western components, which were in many cases hybridised without regard for their origin. We will now review in greater detail the techniques that were responsible for the structural and decorative elements which defined Umayyad architectural forms.19 Wall Building Techniques Ashlar Masonry Umayyad builders largely followed the Roman-Byzantine tradition in their use of ashlar masonry, and continued its technical development to produce outstanding results. Quarrying methods remained virtually unchanged, still involving the use of metal wedges, or plugs, feathers and broad metal chisels.20 Stone quarries were regularly situated near to construction yards, whenever possible and, when no longer in use, would often be transformed into cisterns, ensuring a more stable water supply. Some of the wall paintings preserved at Qusayr ‘Amra ( Jordan) show, among many other technical construction details, the various stages of 19 It must be mentioned that the dating of building techniques relies on up-to-date archaeological assessments based on accurate stratigraphic analysis, carried out in recent decades. 20 Ward-Perkins (1971), Dayyah (2001). LAVAN, LAA4_F23-491-537.indd 503 1/11/2008 6:09:44 PM 504 ignacio arce quarrying, construction and finishing; they illustrate the pre-fabrication of ashlars at the quarry and their subsequent transportation on camels to a remote building site (fig. 2). Apart from seriously reducing the risk of damaging the cargos, the use of camels also made possible the foundation of construction sites in isolated locations, which could not be reached by oxcarts requiring paved roads. A second noteworthy point regarding the Umayyad masonry techniques represented in these paintings is that they involved the abundant use of axes, as well as chisels, in both the extraction and carving (fig. 2) processes. Axes and chisels leave permanent and identifiable cut-traces during the levelling and dressing of a stone surface.21 The dressing and levelling of surfaces with chisels relies on the perimeter anathyrosis of the ashlar face, but if an axe is used, the levelling guides are provided by two series of incised axe-cuts (parallel with each other), following the direction of the two diagonals of the ashlar face. These serve as depth-control guides. After reaching the desired level on these diagonal bands, the final dressing and surface levelling of the rest of the ashlar can begin. The paintings also testify to the use of angle squares, and illustrate the final dressing of the wall surfaces in their entirety (by means of axes in the depicted case), following the construction of the building (fig. 2). Delicate protruding joints made with fine lime mortar can be found in the finest ashlar-built structures (for instance, at Mshatta and Qastal). Meanwhile, for certain structural elements bearing heavy loads, like voussoirs and column drums, precise and delicate joints were produced using anathyrosis. This consisted of a careful levelling of the perimeter band of the contact surface between stressed elements. This technique was designed to prevent the uneven distribution of stress and the appearance of cracks. It can be traced, for instance, at Mshatta. In the area of Syria and Palestine, limestone was mainly used, although it could be combined with basalt for heavily-loaded elements such as jambs, lintels, and thresholds. Basalt could also be used on its own, but only when there was an absence of materials that were easier to carve. The Umayyad basalt-made constructions are usually cruder, and more easily distinguishable than Late Roman buildings, which had more precise joints and more regular courses and faces. 21 Besides, the existence of parallel marks indicates the use of a chisel, while a more random distribution of incisions, a sort of ‘fan’ pattern following the movements of the cutter’s arm, points to the use of an axe. LAVAN, LAA4_F23-491-537.indd 504 1/11/2008 6:09:44 PM umayyad building techniques 505 Fig. 2 Mural paintings. Qusayr ‘Amra ( Jordan). a: Detail of a camel carrying stones from the quarry; b: Detail of axe carving and surface finishing in opera. The technique of emplekton, which involved fitting together two stone faces with a filling, remained widespread. Its mechanical strength was enhanced through the use of headers and stretchers although, in most cases, only the front faces of the blocks were dressed and squared. It is noteworthy that the use of courses consisting only of headers proliferated. These courses were designed to secure walls against seismic disturbances. In other cases, headers were placed in alternating courses that followed a regular pattern. When the header did not pass through the entire girth of the wall, it was usually carved in the shape of a ‘T’, the head of which served to anchor it to the core of the wall. At the same time, the slightly divergent sides of the foot, which were placed perpendicularly to the face of the wall, acted as a dovetail joint that kept in place the stretcher, and were placed between two headers. LAVAN, LAA4_F23-491-537.indd 505 1/11/2008 6:09:44 PM 506 ignacio arce Brick Masonry While Umayyad stone masonry derived mainly from the Roman tradition, it might be argued that Umayyad brick masonry was maily inspired by Partho-Sassanian practice. Brick masonry (and the related pitched brick barrel-vaults that will be described later) was the most significant Mesopotamian contribution to the building technology of the ancient world. Byzantium had, by this time, also succumbed to oriental influence, and developed high-quality brick architecture. Although the Mesopotamian tradition played a more prominent role in Umayyad architecture, variants of both Mesopotamian and Roman brickwork are still present. Roman-Byzantine techniques mainly influenced the hydraulic infrastructure—including the channels, sewers and hypocausts—and used mixed masonry with alternating courses of brick and ashlar masonry (for instance, Anjar, fig. 3). Sassanian techniques were responsible for walls and vaults that were built almost entirely out of brick and incorporated only one or two limestone foundation courses. The latter were implemented to protect superstructures from rising damp, and allowed the construction of huge span-vaults without centring, which were essential given the lack of timber. This Mesopotamian brickwork, as seen in Mshatta and Qasr Tuba, possessed thin, gypsum-based mortar joints, decorated with ‘basketry’ motifs and completely vertical rows of brick (fig. 3). The bricks were quite regular in size, and square in shape. In Mshatta, we can identify two basic sizes: the bricks used for the walls are 29 × 29 cm and th. 7–9 cm, while those used in the vaults were approximately 22 × 22 × 6 cm. Circular-shaped bricks of different dimensions were used in the pilae supporting the suspensurae of the hypocausta. Examples can be found in several Umayyad baths (Mafjar, Hammam As-Sarraj, Ain es-Sil, Mafraq). Adobe (i.e. sun-dried mud bricks) can also be found in Umayyad architecture, as in Qasr Mshash, where square pieces (36–37 × 36–37 × 6 cm) are used, or in the East Palace at Khan Ez-Zebib (39 × 39 × 9 cm), both in Jordan. Other buildings using adobe are found in Syria, at Jabal Says and Qasr al Hayr as-Sharqi. In this last site, two new buildings using this technique have been recently identified (adobe size: 40 × 40 × 10 cm).22 At Qasr Harane ( Jordan), mortar bricks were 22 Guenequand (2003). LAVAN, LAA4_F23-491-537.indd 506 1/11/2008 6:09:48 PM umayyad building techniques 507 Fig. 3 Mixed Limestone and brickwork masonry. a: Qasr al-Hayr as-Sharqi; b: Qasr Tuba; c: Aanjar, ‘Byzantine’ Mixed stone-brickwork masonry; d: Qasr Tuba. Detail of the ‘basketry’ jointing in Sassanian-style brickwork (built on a stone masonry dado). LAVAN, LAA4_F23-491-537.indd 507 1/11/2008 6:09:48 PM 508 ignacio arce used in an unusual way; in decorative friezes and arrow-shaped, slit ventilation openings in façades.23 Irregular Masonry and Mixed Fabrics, Spolia and Anti-Seismic Masonry Features Typical Umayyad rubble masonry walls were composed of irregular, medium-sized, un-squared blocks, held together with lime mortar, mixed with ashes, and joined with fine chipping. They were subsequently plastered with at least two layers of lime-rendering. Herringbone incisions were made on the first of these, which were intended to serve as a grip key for the second.24 Numerous late antique antecedents of this technique exist in the region. In addition, Umayyad walls consisted of horizontal ‘layers’, h. 40 to 80–100 cm, depending on the construction quality and importance of the building.25 Each layer could be composed of one, or several, courses of boulders, of which only the final upper face was levelled horizontally, and covered with a thin layer of lime mortar. This technique should not be confused with the Sassanian practice, to be described below, which made use of boulders and gypsum-based mortar. Some examples of this Sassanian masonry technique can be traced in Umayyad structures, such as Qasr Harane, where it was used extensively throughout the building, or Amman Citadel, where it was restricted to the columns, arches, staircase vaults, and lintels (it is found combined in walls built with the ‘standard’ lime-based mortar technique, described above). It would appear that boulders were embedded in a gypsumbased mortar, and defined regular layers, or ‘courses’. Although these layers may vary in height from 58 to 72 cm, each was kept level overall. The same mortar as that used in the core of the wall was levelled, and employed as a final facing (rendering) of the lateral and upper faces of each ‘layer’, which were executed simultaneously. A new ‘course’, or layer, was built on top of this levelled surface, giving it an appearance similar to that of pise or tapial walls (rammed earthen walls, built 23 Urice (1987). The decorative patterns associated with these bricks are of CentroAsiatic origin. 24 Alternatively, patches of tiny, crushed gravel pressed on the drying surface of the first layer, can be found as grip keys between layers of plaster (e.g. at Umm al-Walid or Qasr Hallabat, in Jordan). 25 These are the respective heights found at the congregational mosque and the dwellings at the Amman citadel. LAVAN, LAA4_F23-491-537.indd 508 1/11/2008 6:09:50 PM umayyad building techniques 509 with the help of wooden formwork). This would lead to the hypothesis that these walls were built with the help of a formwork. However, the absence of vertical joints in each of their ‘courses’ would contradict this theory, considering that it is impossible to build a continuous formwork running along the entire length of a wall. The use of a quick-setting, gypsum-based mortar that gradually stiffened as work proceeded, made possible the construction of this unique masonry without interruption, and even facilitated the ‘decoration’ of its surface with finger markings (‘basketry’ and ‘wavy’ patterns were used) before its final setting. Mixed fabrics, such as the alternating limestone and brick courses at Anjar (fig. 3), were nearly always Roman-Byzantine in origin (a sample from Ghassanid Hallabat had alternating courses of basalt and limestone corresponding to the courses of headers and stretchers). Other walls possessed finely-dressed ashlars on their exterior, and rubble masonry on their interior. The walls of the iwan that preceded the throne hall of the citadel at Amman provide one example. The optimisation of resources seems to have been the general aim: expensive finishing was only applied where necessary, although an appropriate display of luxury was, nonetheless, always present. Naturally, such pragmatic building practices employed large quantities of spolia (mainly lintels, columns, capitals, and marble slabs). One must also note the continuity and further development of antiseismic features, which were no luxury in this earthquake-devastated region.26 These included wooden tie-beams, used in porticoes and inserted in walls, arched lintels with joggled-joints to prevent the lowering of the voussoirs, stone-carved chains in towers (including a complete course of inter-locked, basalt and ashlar masonry fabric), lead sheets placed in the joints of column bases, and the improved system of headers and stretchers, mentioned earlier. Mortars and Lime Production The mortars applied by the Umayyads clearly demonstrate the merging of two different traditions: they used both the western lime-based mortars and eastern, gypsum-based mortars. These were applied according to their specific characteristics, sometimes even within the same building, or the same wall. At the citadel of Amman, for instance, most of 26 For a complete review of these features, see Arce (1996a). LAVAN, LAA4_F23-491-537.indd 509 1/11/2008 6:09:50 PM 510 ignacio arce the masonry consists of lime mortar, while the door lintels and pillar shafts consisted of boulders and were constructed from gypsum mortar. Gypsum-based mortar has a quicker setting time, which means that these elements could have been constructed using simple supports that could be removed after a few hours, or even minutes. At the same time, the shortage of wood in the Syro-Palestinian region meant that the Umayyads could not waste timber by using it as fuel, and forced them to optimise the production of lime. Instead of the traditional ‘high-flame’ lime-kiln (a ‘cooking’ vault situated above a firing chamber, which required a constant fuel supply), ‘lowflame’ kilns were dug out, consisting of single spaces with just a few air holes at their base. In these sunken, conical chambers, limestone layers alternated with long-lasting, high-heat-producing fuels, such as olive pits, nut shells and pine cones. As no additional fuel needed to be added during the firing, this process was much more economic, and the combustion more efficient.27 At what point this type of kiln was initially developed is not yet clear. Whatever the case, the discovery of Umayyad lime kilns at Jerash and in the citadel of Amman, proves that the ‘low flame combustion’ concept is not a modern invention, but much older in date. Structural Roofing Elements The hybridisation discussed thus far was probably most striking in the case of roofing structures. Umayyad arches, vaults and domes contributed to new structural and building concepts and led to a new era in the history of construction.28 Diaphragm Arches, Ribbed Cross ‘Ceilings’ and Vaults A diaphragm arch is a self-standing arch that is placed transversally in a room, in order to reduce the span of its ceiling. The resulting sections can be covered by a lintelled ceiling made of wooden or stone beams, trusses or, alternatively, barrel vaults resting on the arch and the perimeter walls. It is said that this roofing system was devised by the Parthians—the oldest examples come from Ashur, and the palaces 27 28 Arce (2003a). For an in-depth study of these systems, see Arce (2006 in press). LAVAN, LAA4_F23-491-537.indd 510 1/11/2008 6:09:50 PM umayyad building techniques 511 of Taq-i-iwan (Khark) and Hatra (fig. 4)—and later adopted by the Sassanians. It is possible that an early Parthian influence led to the widespread use of diaphragm arches with lintelled ceilings during the Nabatean and Classical periods in the Levant (Syria & Palestine) and, in particular, in the Hawran region (Southern Syria). Conversely, it seems likely that the Umayyads imported the technique of resting transversal barrel vaults on diaphragm arches to the Levant from Iran. This is suggested by the fact that no earlier examples of this variation exist in the region, and it was already present in the earliest Parthian examples: at Ashur (fig. 4) and Khark. Arches could be multiplied and placed in parallel rows, defining regular subspaces or bays, each of them covered independently. This technique was implemented in the prayer halls at Damascus, Cordoba and elsewhere. The arches were also systematically used in residential dwellings, especially as cistern covers, when their span exceeded 5 m. A further development was the use of pairs of arches. These were used to create the first cross-ribbed ceilings, by being crossed perpendicularly and placed across the span of square rooms. The earliest-dated application of this innovative system was discovered at Qasr Harane, and has been dated to the first decades of the 8th c. (fig. 4). Later, as in the mosques of Cordoba and Bab el-Mardún at Toledo (9th–10th c.), the intersecting arches were duplicated, so that ceilings were divided into 9 square, or oblong, sections. The most sophisticated application of this technique entailed the ‘fractal’ repetition of a secondary series of inter-laced arches, covering the square sections defined by the first series (fig. 4). These pairs of arches could be rotated diagonally to the walls. Various combinations of this technique became increasingly sophisticated: 8 arches, arranged into 4 pairs (2 parallel, and 2 rotated diagonally to the walls), were used to define an 8-pointed star. The remaining sections of the ceilings at Cordoba and Toledo were not covered by lintelled coffers, as in the earlier examples from Harane, but by vaults, so producing the first ribbed vaults. This concept would be reproduced much later, both in the mausoleum of the Sultan Sanjar at Merv, and in Gothic architecture.29 29 For an in-depth review of these issues, see Arce (2003a). LAVAN, LAA4_F23-491-537.indd 511 1/11/2008 6:09:51 PM 512 LAVAN, LAA4_F23-491-537.indd 512 ignacio arce 1/11/2008 6:09:51 PM Fig. 4 Diaphragm arches and cross-ribbed vaulting. A&b: Qusayr ‘Amra. Vaults on diaphragm arches; c&e: Harane arches with embedded ribs & first cross-ribbed ceiling; d: Ashur. Parthian palace. Pitched-brick barrel-vaults on diaphragm arches (From Reuther 1939); f: Ukhaidir arch with embedded cast gypsum ribs; g-m: Bab al-Mardún Mosque (Toledo). Cross-ribbed vaults. umayyad building techniques 513 Poly-lobed, Pointed and ‘Horseshoe’ Arches. Reduced-span Centerings The poly-lobed arch is a singular and very characteristic element of Islamic architecture. It has been questioned whether ‘Spanish’ Umayyad builders “transformed oriental decorative shapes into forms of construction, when in most instances, the evolution runs in the opposite direction”.30 The assertion of Ettinghausen and Grabar is based on their belief that this element initially appeared in the mosques of Al Andalus (Cordoba and Bab al-Mardún) when, in fact, the first examples are found in the Early Umayyad mosque at Hallabat in Transjordan.31 At Hallabat, these first poly-lobed arches were situated in the relieving arches above the doors. It is interesting to note that in this tiny mosque, the Umayyad builders experimented with two types of lobe: hollow/concave; and protruding/convex (fig. 5). In the first case—which Fig. 5 Poly-lobed arches. a: Hallabat mosque. Protruding convex lobes; concave lobes; c: Khirbat Mafjar. Polylobed arch and groin vault. 30 Ettinghausen and Grabar (1994) 137. Similar to the case of the first ribbed vaults from these same mosques, described earlier, that also have an earlier antecedent in Bilad al-Sham, at Qasr Harane. 31 LAVAN, LAA4_F23-491-537.indd 513 1/11/2008 6:09:53 PM 514 ignacio arce would become prevalent—the lobe was carved away so that it corresponded with the joint between two voussoirs, while in the second, each protruding lobe was fully carved into the interior of every single voussoir. Both are clever and clear translations of a decorative feature into a structural element. The pointed arch, used in both arches and vaults, is an equally distinctive feature of Early Islamic architecture. It has been suggested that the arch of the Justinianic church of Qasr ibn-Wardan was its earliest antecedent. However, this arch seems instead to have been the result of inadequate centring, or other construction difficulties. The first true pointed arches were built during the Umayyad period. The offset centres of these arches could vary from one-tenth of the span (at Amman, Qasr Tuba and Mshatta, fig. 6), to one-seventh or one-eighth (at Khirbat al Mafjar). The origin of the horseshoe arch is rather controversial, since it was developed almost simultaneously in different areas; Umayyad architecture seems to have drawn on both Sassanian horseshoe arches on decorative plaster, or stone friezes (Harane, Amman, Qastal), and stone-masonry arches from the Byzantine world (Mafjar and Amman). Antecedents of the latter can be traced in Byzantine Syrian churches, like that of Bizzos (6th c.). The actual arch of many masonry-built arches began at a higher level than their formal springing line, since the construction of the first voussoirs, in many cases horizontally-projecting courses, did not require the support of centring devices. In this way, the actual span that had to be crossed with centering was reduced to as little as two-thirds of the original. In many cases, this was combined with voussoirs projecting inwards and outwards (i.e. towards the interior and exterior of the arch), which offered support to span-reduced centrings as, for example, in the vestibule of the citadel at Amman (fig. 6). The inward projection was usually carved away afterwards.32 This procedure had been widespread since the Roman period and several antecedents can be found, for instance, in the Roman temple at Atil in the Hawran (2nd c. A.D.), or in the baths at Philippopolis (3rd c.).33 32 33 For a complete review of these features, see Arce (2003a). Arce (2003a). LAVAN, LAA4_F23-491-537.indd 514 1/11/2008 6:09:57 PM umayyad building techniques 515 Fig. 6 Pointed arches and reduced-span centrings a&b: Amman Citadel Vestibule. Elevation and section of the lateral arches and corresponding semidomes. Notice the span-reduced wooden centring used in the construction of a pointed arch and the projecting voussoirs on which the centring rests. Notice also the parabolic ‘fake’ squinches that allow the transition between the square plan and the the semi-dome that they support: the squinches are not ‘built’ with voussoirs or individual elements, but ‘sculpted’ on the series of projecting horizontal courses of stone masonry, the rest of the semi-dome being ‘built’ with spheric domical voussoirs prefabricated according to the Roman-Byzantine system. Notice as well the Sassanian-origin decorative feature of the niches with horse-shoe arches used, on the one hand, on the upper and lower friezes (where each element is carved on a sole and single stone block interlocked in the ashlar masonry); and on the other one, in the intermediate large panels (where the decorative feature is carved all over a section of masonry wall with disregard for the location of the joints); c&d: Atil (S. Syria) Roman Temple. Reconstruction of the reduced span centring resting on projecting voussoirs system used in the construction of the diaphragm arch; e: Constantinople Hagia Sophia. Detail of the semidome resting on the thick arches that support the central dome (Choisy). LAVAN, LAA4_F23-491-537.indd 515 1/11/2008 6:09:58 PM 516 ignacio arce Vaults 1. Brick Barrel-Vaults Built Without Centering (or ‘Pitched-Brick Vaults’) As mentioned above, brick masonry and its most relevant structural achievement, the barrel-vault without centring, were the most significant Mesopotamian contributions to ancient building technology (the oldest brick vault of this kind, found at Tell al-Rimah in northern Iraq, is dated ca. 2100 B.C.!).34 They had already been adapted in Egyptian structures from the New Kingdom, such as the Ramesseum granaries. These vaults consisted of rings of vertically-laid bricks, which lent slightly to one side. The first bricks were placed against the end wall of the room to be roofed, and rested against rings that had been laid previously (fig. 7). The unusual vertical arrangement of the bricks was held together with quick-setting gypsum mortar. It thus became possible to cover rooms with a large span very quickly. The span could be reduced by using over-hanging horizontal layers of brick, which followed the vault profile, and even by using an offset, marking the false springing-line of the vault. This solution was initially reached in Sassanian Ctesiphon. It was later adopted in the vaults of the unfinished palaces of Mshatta and Qasr Tuba (fig. 7). The laying of bricks on their edges is one of the strangest, but most characteristic features of ancient Mesopotamian and, in particular, Parthian architecture (see above fig. 4). The deployment of this unusual method, which was passed on to the Sassanians and the Umayyads, can be easily explained in the cases of arches and vaults (due to the use of a building technique that did not involve centring). However, it is harder to understand why it was employed in walls or pillars,35 given that it did not contribute to their stability and could only be constructed with fast-setting gypsum mortar.36 The intersection of two barrel vaults built with this technique resulted in a peculiar ‘cloister vault’, often 34 Oates (1996) fig. 28. Examples can be found in the Parthian palace in Ashur: Reuther (1939b) fig. 99a and b and 100. 36 A possible explanation could be related to the fact that baked bricks have less porosity and less water absorption capacity than the mortar employed. Consequently, this lay-out of the brick could eventually reduce the rising damp that was a major threat to brick structures in Mesopotamia. This solution was the result of a trial and error empirical process. Alternatively, it could have been a mere transposition to vertical elements of the method used in vaults. 35 LAVAN, LAA4_F23-491-537.indd 516 1/11/2008 6:10:05 PM umayyad building techniques 517 Fig. 7 Sassanian pitched-brick vaults built without centring a: Sassanian model (From Reuther (1939)); b&d: Mshatta; c: Qasr Tuba; d: Qasr al-Hayr as-Sharqi. found in Khorassan. Herrmann has labelled this, a ‘Quadripartite lanceolated vault’.37 2. Squinch Vaults This was a very peculiar type of vault, which was once again based on Sassanian antecedents,38 and was based on the same structural and technical concepts as the pitched-brick vaults. The construction of a squinch vault started with the placement of a small arched course in each corner of a square room. It proceeded with the addition of new 37 See Herrmann (1999). Also known as khorassani, due to the geographical area where it is commonly found. 38 LAVAN, LAA4_F23-491-537.indd 517 1/11/2008 6:10:05 PM 518 ignacio arce and increasingly large arches, leaning one on top of the other, thereby defining four corner half-cones that met in the centre of each side of the room (fig. 8). The remaining square opening could then be covered by repeating the process, as is still the practice in the houses of the Khorassan region (north-western Iran), or by re-starting the process from the newly-created corners.39 Squinch vaults were apparently hardly ever used in Early Islamic monumental structures, judging by the lack of surviving examples from the period. The only surviving vaults are much later: in the East, there are the Khorassan houses and the congregational mosque in Isfahan (where the vaults date from the 10th c.); in the West, there is the vault of the ‘Cuba’ (from the Arabic, Qubba, or dome), also known as the Fig. 8 Squinch vaults. a: ‘Khorassani’ vault at Merv; b: Sassanian Squinch vault (From Reuther (1939)); d&e: Cuba di S. Domenico. Castiglione, Sicilia. (From Copani, P & Buonanno, L. 2003). 39 Reuther (1939b) fig. 130. LAVAN, LAA4_F23-491-537.indd 518 1/11/2008 6:10:05 PM umayyad building techniques 519 San Domenico ‘church’, or ‘mill’ (fig. 8), near Castiglione in Sicily, that is tentatively dated to between the 11th and the 12th c.40 3. ‘Byzantine’ Mixed Brick and Stone Masonry Vaults Brick vaults of the Byzantine tradition can be identified in several Umayyad buildings. The first courses of voussoirs in the majority of these vaults—which proceeded from the springers and did not require a centring to be laid—were cut in limestone. The rest of these vaults were executed in brickwork. In Khirbat al Mafjar, there are examples of barrel and cross (or groined), vaults, and a dome on pendentives, which was constructed from this mixed brick-stone masonry.41 Vaults have been found which comprise a mixture of techniques; put together with stone slabs, or even light concrete (using volcanic tuff ), instead of brick, and displaying a great variety of building solutions.42 Nevertheless, it must be stressed again that the technical hybridisation of Roman and oriental techniques had already started in the late antique period, for instance, in the un-centred and pitched brick-vaults constructed by Byzantine masons. Indeed, Byzantine masons had perfected the use of 43 transversal arches to sub-divide large areas into small sections, which were filled up using an improved version of the old Mesopotamian method. Examples of this practice are evident in the Byzantine cistern at the Aleppo citadel, or at Qasr ibn-Wardan (both in Syria). However, it is curious that modifications of the Byzantine pitched-brick vaults with thick mortar joints and inclined rows of bricks were never applied by the Umayyads, who preferred the original ‘Sassanian’ technique.44 Domes, Squinches and Pendentives The Umayyad fusion of two cultural models is also apparent in their structural systems, particularly in their use of both squinches (originally an Iranian invention) and pendentives (the most outstanding achievement of Syro-Byzantine masons) to support domes. This fusion fundamentally influenced their construction of domes. These were made in various shapes—for example, hemispheric or ‘umbrella’-shaped—and 40 41 42 43 44 Copani & Buonanno (2003). Hamilton (1959) figs. 36–41. Arce (2006) in press. Choisy (1883). See above and in Arce (2006) in press. LAVAN, LAA4_F23-491-537.indd 519 1/11/2008 6:10:07 PM 520 ignacio arce could be executed in a range of materials, such as limestone, shale,45 volcanic tuff 46 or, as in the Dome of the Rock, timber. 1. Domes on Squinches The Sassanian domes on squinches can be seen as a particular type of the squinch vault described above. The half-cones in each of the 4 corners of these domes did not reach as far as the middle of the room. Instead, some space was left between them that was filled with horizontal courses. These resulted in a horizontal circle at the crown of the squinch arches, on which the domes would rest. Such domes had a half-elliptical section, and were built with horizontal circular courses, made of gypsum mortar and without centring (fig. 9). In the dome erected over squinches in the Sassanian palace at Sarvistan (Iran), the transition section, formed by the drum with the squinches, was made of cobbles and roughly-cut stones embedded in gypsum mortar (as were most of the building’s walls), while the dome itself was built with bricks. Meanwhile, in the dome over squinches at the Firuzabad Palace (Ardashir’s Palace, 3rd c.), both the squinches and the dome were built with cobbles embedded in gypsum mortar.47 At Qasr Harane, (an Early Umayyad structures dating to the first decades of the 7th c.) different examples of these squinches can be seen (fig. 9). They feature shapes and techniques from the Sassanian tradition. The ‘Reception Hall’ at the Amman Citadel featured a Sassanian dome on parabolic-conoidal squinches (figs. 6 & 9), which was built in stone with the means and know-how of local stone-cutters of the Byzantine tradition. It is an extraordinary example of the unexpected results obtained from this merging of techniques and shapes in the first half of the 8th c. The translation into stone of shapes with no possible stereometric solution posed a real challenge to the experienced stonecutters responsible. They rose to the task cunningly by carving or, rather, sculpting the shape of these squinches out of a series of overhanging and horizontal stone courses. These horizontal courses 45 For example, the one which had disappeared at Hammam as Sarraj. For example, at Hallabat. 47 Reuther (1939). This building technique, and in general, Sassanian architecture, could be described as an architecture of ‘plaster-masons’ (see figs. 5, 18 & 19), while the Syrian-Byzantine tradition was an architecture mainly produced by ‘stonecuttermasons’ (see figs. 13 & 30); terms coined and often used by Tiziano Mannoni, who distinguishes between muri da muratori and muri da scalpellino, i.e. plaster masonry vs. stone-cutting masonry. 46 LAVAN, LAA4_F23-491-537.indd 520 1/11/2008 6:10:07 PM umayyad building techniques 521 Fig. 9 Squinches. a&b: Harane (three different kind of squinches); c: Amman Citadel Vestibule. ‘fake’ squinches (Note the different building technique used in the lower and the upper section of the structure) d&e: Sarvistan (Iran). reached the level of the crown of the squinches, which corresponded to the semi-circumference on which the parallel semi-dome rested. From that level, the stone-cutters constructed the semi-dome according to the ‘standard’ Byzantine method of building stone domes; with the use of spherical and radial joints. A unique case of lintelled squinches supporting a dome is displayed in the Amman citadel throne hall. This unicum is another example of the translation into stone of a Partho-Sassanian shape, in this case originally conceived in timber. Antecedents of this element can be traced in the Parthian Palace at Nisa. This is unsurprising, given that it had been a standard roofing system in northern Iran and neighbouring regions, such as Azerbaijan, Georgia, Armenia and Tajikistan.48 To a certain extent, it followed the principle of the squinch vault, although, instead of arches, it included horizontal beams that were placed diagonally. These defined a series of squares, which were inscribed within one another and rotated 45 degrees (fig. 10). 48 For a complete review of these features, discovered during the excavation and restoration project, see Arce (2000): “Un tipo inédito de trompas en la arquitectura omeya”. LAVAN, LAA4_F23-491-537.indd 521 1/11/2008 6:10:07 PM 522 ignacio arce Fig. 10 Dome on ‘lintelled squinches’, from Amman Citadel Throne Hall. c-h: Reconstruction by the Author based on material evidences found in situ. Antecedents in timber from, a: Nisa. Parthian Palace (Pugachenkova); b: Caucasus region (Azerbaijan, Georgia & Tajikistan). 2. Domes on Pendentives The following examples of domes on pendentive illustrate that the high levels of excellence reached by Syro-Byzantine stone-cutters were developed and improved during the Umayyad period, and that classical stereotomy reached its apogee in Umayyad buildings. In fact, pendentives might be viewed as the most important achievement of late antique stone-carved masonry. First of all, the pendentives from the bath hall of Mafjar merit discussion.49 ‘Normal’ pendentives are basically the shape of a hemisphere, and are intersected by 4 planes that rise vertically from the sides of the square to be covered (inscribed in the circumference base of the sphere). In this way, they create vertical, semi-circular arches in the lateral cut sides of the hemisphere. The modified pendentives from Mafjar are an extraordinary geometrical tour de force. Their basic figure is smaller than a hemisphere, while their 4 intersecting planes constitute the sides of a pyramid. Thus, the resulting arches are parabolic in shape, and are in an inclined, rather than vertical, plane. This means that the builders 49 Hamilton (1959) 81 and fig. 42. LAVAN, LAA4_F23-491-537.indd 522 1/11/2008 6:10:10 PM umayyad building techniques 523 must have added sections of barrel vaults to reach the semi-circular sides of the room. Further examples include the exedrae at Mafjar and Hammam AsSarraj. These both possessed semi-domes that had been built in courses that radiated centrally from their rear.50 At Mafjar, the stone-cutters displayed their expertise in a rather eccentric manner: they suspended a chain of cut stone from the apex of the semi-dome. It ended in a sort of tear-like pendant (fig. 11). All of the pieces of this feature (including the inter-locking links of the chain) were carved from a single piece of limestone.51 The fragments of a dome on pendentives, recently retrieved from the mosque at Hallabat, constitute our final example of this technique.52 Fig. 11 Semi-dome & niche built in courses radiating from the back: Khirbat al-Mafjar. 50 Hamilton (1959) figs. 49a and b. “The cross-shaped piece at the top from which the whole ‘chain’ hangs is a true domical voussoir; in the construction it must have been kept to the last, cut ready with its chain, and finally dropped into place to close the structure.” Hamilton (1959) 91. 52 A feature discovered by the author during the ongoing excavation and restoration project carried out at the site, not yet published. 51 LAVAN, LAA4_F23-491-537.indd 523 1/11/2008 6:10:13 PM 524 ignacio arce The remains of this dome testify to a more formal constraint and technical proficiency. Whereas the spherical triangles, or pendentives, were normally separated from and constructed after the 4 supporting lateral arches, in Hallabat, the voussoirs of the arches, and the neighbouring sections of the pendentives, were carved from the same block. These features make this dome a technical antecedent of those dating from the Spanish and French Late Renaissance, the period in which stereotomy—and geometry in general—is supposed to have reached its climax. Pre-cast Gypsum Structural Elements Pre-cast gypsum structural elements are purely Sassanian in origin. They include ribs functioning as formwork, or temporary centring in the construction of arches (fig. 12),53 and the capital-plaques from which the ribs spring, are purely Sassanian in origin. They can be found in important Umayyad buildings, like the Amman citadel and Qasr Harane.54 Surface Decoration: Mosaics, Mural Painting and Carved Stucco Decorative Patterns and Concepts: Surface vs. Structure The principles behind the relationship between structure and decoration in the eastern and western traditions, which were discussed earlier, can also help us to better understand the specific characteristics of Umayyad decorative techniques. Here again, the same two main characteristics can be clearly distinguished: mosaics and mural paintings from the classical world; and oriental gypsum-plaster stucco. 1. Mosaics In Late Antiquity, Bilad al-Sham had a long-lasting tradition of mosaic production, especially during the 5th and 6th centuries.55 The tradition 53 Arce (2003a). Arce (2001a). 55 During this period (7th–8th c. A.D.), this technique disappeared from the rest of the Mediterranean. Meanwhile, it blossomed in the Islamic Levant. 54 LAVAN, LAA4_F23-491-537.indd 524 1/11/2008 6:10:13 PM umayyad building techniques 525 Fig. 12 Gypsum pre-cast structural elements. Niches, ribs and ‘capitalplaques’. a: Sassanian niches from Ctesiphon; Umayyad niches: Jabal Says (b&d) and Qasr al Hayr as-Sharqi (c); Embedded ribs and ‘capital-plaques’: Harane (e); Amman Citadel (f&g) and Ukhaidir (h). LAVAN, LAA4_F23-491-537.indd 525 1/11/2008 6:10:13 PM 526 ignacio arce was revived in the Umayyad Period after the hiatus of the Sassanian invasion. It was adopted by the new rulers to decorate the luxury pavements that were designed as status symbols.56 These pavements were used extensively, not only on floors, but also on walls and domes. Examples include the parietal mosaics on the drum of the Dome of the Rock, those on the barrel-vaults of the entrance canopies of the same building, and the traces found on the ‘dome on pendentives’ at Qusayr ‘Amra. Mosaics were one of the few decorative techniques used by the Umayyads in which no Partho-Sassanian influence can be identified. Indeed, even the decorative patterns they used are predominantly Byzantine.57 However, it would appear that the Umayyads increasingly favoured purely geometric patterns which accorded with the Islamic prohibition of figurative representation.58 From the Hellenistic period onwards, the design and execution of mosaics improved considerably. The transition from the bi-chromatic mosaics of the Hellenistic period, to the Byzantine and Umayyad mosaics, which incorporated glass tesserae and gold leaf, was accompanied by the evolution and improvement of mosaic beds.59 56 This tradition would also be kept alive by Christian communities until the 9th c. A.D. This was possible because, although the covenant of the Caliph Omar prohibited the construction of new churches, it still allowed the refurbishment and re-decoration of existing ones. 57 Only a few features of Sassanian origin can be recognised at the Dome of the Rock. 58 Especially after the iconophobe decree of Caliph Yazid, which ordered the removal of the majority of the mosaics of the churches of Bilad Al Sham. Remarkably, the promulgation repeated the iconoclastic revolution of the Byzantines, a century earlier. 59 “The small black and white limestone and black tesserae of the mosaic floor in the apodyterium of the Herodian fortress of Machaerus, dated to the 1st c. B.C., were laid upon a layer of lime a few millimetres deep which, in turn, had been laid on a shallow bed of stone chips embedded in a mortar of lime mixed with ashes. In the vestibule and side rooms of the earliest church dedicated to Moses on Mount Nebo, dated to the late 4th c. to early 5th c. A.D. dull white cubes, larger than those used in the polychrome pavements of the sanctuary, were set in a layer of mortar directly on the bedrock . . . The mosaicist who created the polychrome compositions of the 2nd half of the 4th c. A.D. commonly used a bed composed of different layers. The soil was settled with a compact layer of local red earth (terra rossa). On top of this was a layer of small round pebbles placed close to each other and covered by a layer of lime with ashes mortar. This smooth bed covered the whole area to be decorated to a thickness not exceeding 15 cm, and on it was spread a layer of wet lime plaster (usually not more than 1 cm thick). This was done in stages according to the area the mosaicist could work on before the plaster became dry. Normally the mosaicist would draw the outlines of the composition in red; then he would start laying the tesserae. These were cubes of 1 cm, cut from local limestone, basalt, jasper or oil shale” . . . “Sometimes glass tesserae were used for rare colours such as green and blue” . . . Piccirillo (1993) 19–23. LAVAN, LAA4_F23-491-537.indd 526 1/11/2008 6:10:14 PM umayyad building techniques 527 2. Wall Plaster and Mural Paintings Although very few mural paintings have been preserved from the Umayyad period, they are significant because of the motifs and scenes they portray. These vividly depict the life and customs of the new Umayyad rulers. The best preserved and most famous are undoubtedly those from Qusayr ‘Amra (fig. 2).60 Traces of similar murals have been discovered in other Umayyad palaces, like the complexes of Qasr Hallabat, the Hammam at Sarraj,61 and Qasr el Hayr East and West (which also has important floor paintings.)62 Although usually referred to as frescoes, they were actually painted a secco, i.e., the pigments were diluted in a lime-based media and then painted onto a mortar layer that had been applied at an earlier stage. These paintings were still created using the Roman technique of applying the paint onto a fine layer of white lime (intonaco) which, in turn, covered a thick levelling layer (arriccio) of lime plaster—usually consisting of a poor quality lime with ashes. A herring-bone pattern was sometimes incised into the surface of the preparatory plaster. This would, during the Umayyad period, in many cases, be combined with, or sometimes replaced by, crushed basalt stone or gravel, offering an even better hold for the final plaster layer. Examples can be found at Umm Al-Walid, Qasr Hallabat, and another variant at the Amman Citadel mosque.63 3. Carved Stucco Gypsum plaster and stucco were used in building work because they were cheap, easy to work with, flexible and versatile. They could be used in three-dimensional sculptures, decorative panels, window grills and, as seen above, load-bearing elements. Their widespread adoption in the Umayyad period solved the huge and pressing demand for construction work. Once again, the merging of techniques and formal repertoires generated a novel, hybrid result. The main distinction between Sassanian and Umayyad stucco is that the first was mostly stamped onto plasterwork with moulds, whether directly onto walls, or onto serial manufactured tiles (fig. 13), or moulded 60 Almagro et al. (1975). Bisheh (1980) and Arce (2004). 62 Creswell (1969). 63 See Arce (2004) and (2000) in press. Note that these methods are the same as those employed in ‘standard’, rather than ‘decorated’, plastering. 61 LAVAN, LAA4_F23-491-537.indd 527 1/11/2008 6:10:14 PM 528 ignacio arce Fig. 13 Stucco. a: Sassanian pre-cast or moulded gypsum plaques (true antecedents of decorated wall tiles); b: Qasr al-Hayr al Gharbi (Syria) Main entrance. Stucco panels applied in a ‘wallpaper fashion’, with disregard to the structure on which it is laid upon; c: Khirbat al-Mafjar. Unfinished chiselled stucco panel (From Hamilton (1959)); d: Sassanian stamps for stucco; e: Petra. Qasr al-Bint Hellenistic-style stucco architectural lining. LAVAN, LAA4_F23-491-537.indd 528 1/11/2008 6:10:14 PM umayyad building techniques 529 plaques.64 In contrast, the patterns of Umayyad stucco were mostly carved manually onto the plaster while it was still soft.65 In this case, as with the giornate of fresco paintings, it was necessary to apply only as much plaster as could be decorated in one day. Thus, joints can always be traced in the finished painting. Nevertheless, free-hand carved stucco can also be found in Sassanian architecture, and in the moulded plaques and stamps of Umayyad buildings. The decorated roundels at Qasr Harane serve as an example of the latter.66 The standard Umayyad technique usually comprised the insertion of levelling layers of lime mortar plaster (similar to those used in mural paintings and wall rendering) under the final gypsum-plaster layer. Once again, this is an example of a ‘technical merging’ of Sassanian and classical practices.67 Before it dried and hardened, the final layer of gypsum-made stucco was carved and modelled directly onto the hardening plaster with a blade, or putty knife. The chiaroscuro effect was reinforced with holes that were drilled into specific points (piercing beads or, where the main lines of the design changed direction, the stems and branches of leaves). The carving was most probably carried out with a triangular, in-section chisel, knives and drills. Consequently, the results of this craftsmanship are more expressive than the ornamental pieces of stiff plaster stamped with moulds. The firmly-established tradition of stone-carving in Byzantine Syria must have influenced some of the techniques responsible for Umayyad carved stucco. It is possible that these were technically superior to those employed within the Partho-Sassanian tradition. The use of preciselydrawn guidelines in geometric patterns bears this out. It is probable that some of the Sassanian ‘all encompassing’ (or ‘infinite’) geometric patterns were also executed by using preparatory drawings. However, the abandonment of stamping moulds and the very articulated architecture within which these were applied, necessitated the improvement of these preparatory drawings. 64 Arce (2001a) fig. 3 and Baltrusaitis (1939). For a complete review of these features, see Arce (2001a): “The Early Islamic Stucco Technique and the Partho-Sassanian Tradition.” 66 Urice (1987) figs. 89 and 91. Once more show how closely this building related to original Sassanian technical traditions. 67 This mixed technique sometimes made it difficult to attach the final layer of decoration, due to its weight and the insufficient grip provided by the incised herringbone-pattern keys. This often caused the detachment and eventual collapse of complete sections of panels. 65 LAVAN, LAA4_F23-491-537.indd 529 1/11/2008 6:10:17 PM 530 ignacio arce Attempts to adapt decorative patterns to architectural structures can also be identified. In our opinion, this represented the main contribution of Syro-Byzantine craftsmanship, and determined the ‘westernised’ character of this eastern technique. Nonetheless, it should be noted that, in most of the cases, the traditional lack of correspondence between decoration and structure, inherited from the Persian tradition, was still predominant (fig. 13). According to Hamilton, who studied the unfinished panels found at Mafjar, the instruments used in the preparatory drawings included a ruler, a scoring tool, a blunt point, dividers and a taut string. Most of the base drawings were composed of equilateral triangles. Others were drawn on squares, parallel to each other, tilted 45 degrees, or etched into inter-laced and equal circles.68 Despite the use of preparatory grid base-drawings, the geometric pattern was eventually applied with little attention to the edges that framed it. Therefore, in order to obtain a neat finish, the pattern was surrounded by a sort of frame that closely resembles the geometric, or ‘infinite’, patterns found on oriental rugs (fig. 13). It is also reminiscent of the use of wallpaper, or textiles, as wall linings (Hamilton very accurately uses the term ‘wallpaper treatment’ to describe the result). Hamilton points out that the main difference between the use of similar ‘infinite’ patterns by Christian Syrian sculptors and their Umayyad counterparts is that the former always adapted their pattern to the proportions of the field, so that ‘no fraction of a unit was left over the edges’.69 The procedure followed by the Umayyads had its origins in the original Sassanian stucco tradition, which used mould-stamps and tiles, or moulded plaques. When a repetitive pattern was applied by means of a stamp (or when pre-cast plaques were used as a cladding), a preparatory drawing was not necessary, as the mould or stamp was printed repeatedly onto one field until it was completely covered. Inevitably, fragments of the basic unit were left on the edges of the field. The traditional Syro-Byzantine procedure and concept design can only be detected in some of the pre-fabricated balustrade panels from Mafjar (fig. 13). It corresponds to the stone-carving techniques displayed by the marble-carved screen panels, in which the design was composed within a field, and was treated as if it had been framed, and the design 68 69 Hamilton (1959) 273 and plates LXI & LXII. Hamilton (1959) 280. LAVAN, LAA4_F23-491-537.indd 530 1/11/2008 6:10:17 PM umayyad building techniques 531 composed precisely within it.70 In such cases, it seems that the panel was not carved, or chiselled, while it was still soft, but was first left to dry completely. In the panels found at Hallabat,71 an intermediate approach can be detected: Sassanian techniques were used to execute a Syrian design, consisting of panels which were framed and articulated by architectural elements. Such designs were thus more closely related to the architectural support. The co-existence of both methods, and the merging of concepts in the architectural features of one building, again reinforce the hypothesis that Syrian and Mesopotamian craftsmen were working together, sharing and interchanging experiences and knowledge in order to reach a new and unique result: the synthesis of two cultural and artistic traditions. Conclusion The experimental process of merging of western and eastern architectural models and building techniques during the Umayyad period contributed to a new architectural and urban tradition that was to liberate Islamic material culture from Antiquity. It can be seen as one element of a general process of transformation, driven by the attempts of Umayyad rulers to establish new administrative, political and economic frameworks in place of those inherited from Late Antiquity. It is important to note that this combination of artistic trends provided a new catalogue of techniques and styles that defined the emerging culture (and its corresponding image of power) and, at the same time, guaranteed the survival of ‘antique’ cultural practices and elements from the eastern and western traditions that would otherwise have been lost. This balance between continuity and change is particularly striking in the case of the city. Here, an ‘urban culture’ was preserved thanks partly to the transformation process it underwent, and partly to the strong monetary economic system that was developed. Far from neglecting the ‘classical city’, these factors led to its revival and transformation in the Near East. The strength of the new and hybrid culture triggered transformation elsewhere in the Mediterranean basin. Indeed, a similar transforma- 70 71 Hamilton (1959) 280. Restored by the author. LAVAN, LAA4_F23-491-537.indd 531 1/11/2008 6:10:17 PM 532 ignacio arce tion from Antiquity to a new era took place in some other areas under Islamic control, such as in Spain (al-Andalus). Bibliography Almagro M., Caballero L., Zozaya J. et al. (1975) “Qusayr ‘Amra. Residencia y baños Omeyas en el desierto de Jordania”, (Madrid 1975). Almagro A. and Arce I. (1996) “El alcazar Omeya de Amman, crisol de técnicas constructivas”, in I Congreso Nacional de historia de la Construccion (Madrid 1996) 26–30. Arce I (2006) “Qasr Hallabat ( Jordan) revisited: reassessment of the material evidence”, in Muslim Military Architecture in Greater Syria: From the Coming of Islam to the Ottoman Period, ed. H. Kennedy (History of Warfare 35) (Leiden 2006). ——. (forthcoming a) “Umayyad arches, vaults and domes: merging and re-creation. Contributions to Early Islamic construction history”, in Proceedings of the 2nd International Congress on Construction History (Cambridge, March 2006) (forthcoming). ——. (forthcoming b) “Qasr al-Hallabat: Continuity & Change from the Roman-Byzantine to the Umayyad Period”, SHAJ IX (Amman forthcoming). ——. (2004) “The Umayyad hydraulic system at Amman Citadel—collection, storage, distribution, use and sewage”, in Men of Dikes and Canals: The Archaeology of Water in the Middle East (Orient-Archäologie Band 13) edd. H. Bienert, and J. Haesser (Petra 1999) 243–60. ——. (2003a) “From the diaphragm arch to the ribbed vault. An hypothesis for the birth and development of a building technique”, in Proceedings of the First International Congress on Construction History, ed. S. Huerta (Madrid 2003) 225–41. ——. (2003b) “Early Islamic lime kilns from the Near East. The cases from Amman Citadel”, in Proceedings of the First International Congress on Construction History, ed. S. Huerta (Madrid 2003) 213–24. ——. (2001a) “The Early Islamic stucco technique and the Partho-Sassanian tradition”, in Lo stucco. Cultura, tecnologia, conoscenza (Scienza e Beni Culturali XVII) edd. G. Biscontin and G. Driussi (Venice 2001) 107–23. ——. I. (2001b) “The Umayyad carved stucco from Amman Citadel congregational mosque”, in Lo stucco. Cultura, tecnologia, conoscenza (Scienza e Beni Culturali XVII) edd. G. Biscontin and G. Driussi (Venice 2001) 125–40. ——. (2000) “Un tipo inédito de trompas en la arquitectura omeya”, in Actas del Tercer Congreso Nacional de Historia de la construcción: Sevilla, 26 a 28 de octubre de 2000 ed. A. Graciani García, vol. 1 (Madrid 2000) 37–48. ——. (2002) “The Umayyad congregational mosque and the Souq Square complex at Amman Citadel. architectural features and urban significance”, in Proceedings of the Second International Congress on the Archaeology of the Ancient Near East, Copenhagen 2000. Vol. 2 (on Islamic Archaeology) ed. I. Thuesen (Winona Lake 2002). ——. (2003) “Elementos y sistemas constructivos antisísmicos en la antigüedad. Aplicación a la restauración de estructuras históricas”, in Proceedings of the First International Congress on Construction History, ed. S. Huerta (Madrid 2003) 39–47. ——. (1996b) “El estudio de los acabados y revestimientos de la arquitectura”, in Arqueología de la. arquitectura: el método arqueológico aplicado al proceso de estudio y de intervención en edificios históricos: actas, Burgos, 1996 (Valladolid 1996) 87–102. LAVAN, LAA4_F23-491-537.indd 532 1/11/2008 6:10:17 PM umayyad building techniques 533 Baltrusaitis J. (1939) “Sassanian stucco”, in A Survey of Persian Art ( London 1939) 601–30. Bisheh G. (1993) “From Castellum to Palatium: Umayyad mosaic pavements from Qasr Al-Hallabat in Jordan”, Muqarnas 10 (1993) 49–56. Bujard J. (1995) “La fortification de Kastron Mayfa’a/Umm ar-Rassas”, SHAJ.V,DoA (Amman 1995) 241–49. Butler H. C. (1909) Publication of the Princeton University Archaeological Expedition to Syria in 1904–5 and 1909 Div.2 Section A (Leiden 1909). Chehab M. (1953) “The Umayyad Palace at Aanjar”, Ars Orientalis 5 (1953) 17–27. Choisy A. (1873) “L’art de bâtir chez les Romains”, in Librairie générale de l’architecture et des travaux publics Ducher et Cie (Paris 1873). Choisy A. (1883) L’art de bâtir chez les Byzantins Librairie de la Société Anonyme de Publications Periodiques (Paris 1883). Copani P. and Buonanno L. (2003) “The “Cuba” near Castiglione in Sicilly. A self-supporting vault made of volcanic stone”, , in Proceedings of the First International Congress on Construction History, ed. S. Huerta (Madrid 2003) 611–21. Creswell K. A. C. (1989) A Short Account of Early Muslim Architecture (Oxford 1989). ——. (1969) Early Muslim Architecture vol. 1. (Oxford 1969). Dayyah A. (2001) “Selected Roman stone quarries in Central Jordan: a cultural resource”, ADAJ (2001). Ettinghausen R. and Grabar O. (1994) The Art and Architecture of Islam 650–1250 (New Haven, Connecticut and London 1994). Ewert C. (1973) “Die Moschee von Mértola”, Madrider Mitteilungen 14 (1973) 217–46. Frankfort H. (1970) The Art and Architecture of the Ancient Orient (London 1970). Guenequand D. (2003) “Rapport préliminaire de la campagne de fouille 2003 à Qasr al Hayr As-Sharqi et al-Bakhra (Syrie)”, Schweizerisch-Liechtensteinische Stiftung fur Archaölogische Forschungen im Ausland, Jahresbericht 2003 (Zurich 2003) 69–98. Grabar O. (1973) The Formation of Islamic Art (London 1972). Grabar O. (1959) “The Dome of the Rock”, Ars Orientalis 3 (1959) 33–62. Hamilton R. (1959) Khirbat Al-Mafjar: An Arabian Mansion in the Jordan Valley (Oxford 1959). Herrmann G. (1999) Monuments of Merv. Traditional buildings of the Karakum (London 1999). Kennedy D. (2004) The Roman Army in Jordan (London 2004). Oates J. (1996) Babylon (London 1996). Parker S. T. (1986) Romans and Saracens: A History of the Arabian Frontier (Winona Lake 1986). Piccirilo M. (1993) Mosaics of Jordan (Amman 1993). Pope A. U. (1939) ed. A Survey of Persian Art (London 1939). Reuther O. (1939b) “Sassanian Architecture”, in A Survey of Persian Art, ed. P. U. Pope (London 1939) 493–578. ——. (1939a) “Parthian Architecture”, in A Survey of Persian Art, ed. P. U. Pope (London 1939) 411–44. Urice S. K. (1987) Qasr Kharana in the Transjordan (Durham. N.C 1987). De Vries B. (1998) ‘Umm el-Jimal: A Frontier Town and its Landscape in Northern Jordan’ Volume I Fieldwork 1972–1981 ( JRA Supplementary Series 26) (Portsmouth, Rhode Island 1998). Ward-Perkins J. B. (1971) “Quarrying in antiquity, technology, tradition and social change”, Proceedings of the British Academy 57 (1971) 137–58. Watelin L. (1939) “The Sassanian buildings near Kish”, in A Survey of Persian Art, ed. A. U. Pope (London 1939) 584–92. Whitcomb D. (1998) Aqaba, Port of Palestine on the China Sea (Chicago 1998). LAVAN, LAA4_F23-491-537.indd 533 1/11/2008 6:10:18 PM 534 ignacio arce List of Figures All pictures and drawings (except where stated otherwise) by the author. Fig. 1. Translation of shapes and techniques. a: Khirbat al-Mafjar. Bath Porch. Stonecarved ‘corinthian’ capital. This capital imitates the features of the gypsum-carved Sassanian version of the classical model; b: Machaereus ( Jordan). Herodian fortress. Ionic capital, with decorative features applied in stucco onto a stone core; c: Amman Citadel. Capital carved into stone imitating Sassanian models carved in stucco; d: Amman Citadel Mosque. Capital. Restoration carried out by the author based on the remains found in situ. The decoration in carved stucco was applied onto the stone core, except the lower part of the capital (facing down) that was carved on the stone core itself. Fig. 2. Mural paintings. Qusayr ‘Amra ( Jordan). a: Detail of a camel carrying stones from the quarry; b: Detail of axe carving and surface finishing in opera. Fig. 3. Mixed Limestone and brickwork masonry. a: Qasr al-Hayr as-Sharqi; b Qasr Tuba; c: Aanjar, “Byzantine” Mixed stone-brickwork masonry; d: Qasr Tuba. Detail of the “basketry” jointing in Sassanian-style brickwork (built on a stone masonry dado). Fig. 4. Diaphragm arches and cross-ribbed vaulting. A&b: Qusayr ‘Amra. Vaults on diaphragm arches; c&e: Harane arches with embedded ribs & first cross-ribbed ceiling; d: Ashur. Parthian palace. Pitched-brick barrel-vaults on diaphragm arches (From Reuther 1939) f: Ukhaidir arch with embedded cast gypsum ribs; g-m: Bab al-Mardún Mosque (Toledo). Cross-ribbed vaults. Fig. 5. Poly-lobed arches. a: Hallabat mosque. Protruding convex lobes; concave lobes; c: Khirbat Mafjar. Polylobed arch and groin vault. Fig. 6. Pointed arches and reduced-span centrings a&b: Amman Citadel Vestibule. Elevation and section of the lateral arches and corresponding semidomes. Notice the span-reduced wooden centring used in the construction of a pointed arch and the projecting voussoirs on which the centring rests. Notice also the parabolic ‘fake’ squinches that allow the transition between the square plan and the the semi-dome that they support: the squinches are not ‘built’ with voussoirs or individual elements, but ‘sculpted’ on the series of projecting horizontal courses of stone masonry, being the rest of the semi-dome ‘built’ with spheric domical voussoirs prefabricated according to the Roman-Byzantine system. Notice as well the Sassanian-origin decorative feature of the niches with horse-shoe arches used, on the one hand, on the upper and lower friezes (where each element is carved on a sole and single stone block interlocked in the ashlar masonry); and on the other one, in the intermediate large panels (where the decorative feature is carved all over a section of masonry wall with disregard for the location of the joints); c&d: Atil (S. Syria) Roman Temple. Reconstruction of the reduced span centring resting on projecting voussoirs system used in the construction of the diaphragm arch; e: Constantinople Hagia Sophia. Detail of the semidome resting on the thick arches that support the central dome (Choisy). Fig. 7. Sassanian pitched-brick vaults built without centring a: Sassanian model (From Reuther (1939)); b&d: Mshatta; c: Qasr Tuba; d: Qasr al-Hayr as-Sharqi. Fig. 8. Squinch vaults. a: ‘Khorassani’ vault at Merv; b: Sassanian Squinch vault (From Reuther (1939)); d&e: Cuba di S. Domenico. Castiglione, Sicilia. (From Copani, P. & Buonanno, L. 2003). Fig. 9. Squinches. a&b: Harane (three different kind of squinches); c: Amman Citadel Vestibule. ‘fake’ squinches (Note the different building technique used in the lower and the upper section of the structure) d&e: Sarvistan (Iran). Fig. 10. Dome on ‘lintelled squinches’, from Amman Citadel Throne Hall. c-h: Reconstruction by the author based on material evidences found in situ. Antecedents in LAVAN, LAA4_F23-491-537.indd 534 1/11/2008 6:10:18 PM umayyad building techniques 535 timber from, a: Nisa. Parthian Palace (Pugachenkova); b: Caucasus region (Azerbaijan, Georgia & Tajikistan). Fig. 11. Semi-dome & niche built in courses radiating from the back: Khirbat alMafjar. Fig. 12. Gypsum pre-cast structural elements. Niches, ribs and ‘capital-plaques’. a: Sassanian niches from Ctesiphon; Umayyad niches: Jabal Says (b&d) and Qasr al Hayr as-Sharqi (c); Embedded ribs and ‘capital-plaques’: Harane (e); Amman Citadel (f&g) and Ukhaidir (h). Fig. 13. Stucco. a: Sassanian pre-cast or moulded gypsum plaques (true antecedents of decorated wall tiles); b: Qasr al-Hayr al Gharbi (Syria) Main entrance. Stucco panels applied in a “wallpaper fashion”, with disregard to the structure on which it is laid upon; c: Khirbat al-Mafjar. Unfinished chiselled stucco panel (From Hamilton (1959)); d: Sassanian stamps for stucco; e: Petra. Qasr al-Bint Hellenistic-style stucco architectural lining. Glossary Adobe. Sun-dried mud brick. Anathyrosis. Joint surface treatment by which the perimeter of the faces of each block or element is finely carved and smoothed to provide a neat and precise joint with the neighbouring block. In the case of ashlar carving, anathyrosis usually adds to the visible face of the block a recessed perimetral surface band, while the rest of the block face is usually not carved so accurately, or is even left with a rough and protruding finish. In this case, we have ‘rusticated ashlar’, and ‘rusticated masonry’ work. Where column drums, or other linear, load-bearing elements, are concerned, the internal area of the smoothed perimeter band of the hidden face of the joint is carved away, leaving a hollow void. By doing this, the load is evenly transmitted simply by means of the smoothed perimeter band, avoiding the harmful occurrence of local tensions and the concentration of stress that can create cracks and even provoke the collapse of the structure. Apadana. Building used for royal receptions by the Achaemenid kings. This kind of audience hall consisted of a huge square room covered by a flat roof, which was made of wooden architraves and supported by a ‘forest’ of columns placed on a regular and orthogonal grid pattern. The most famous example is that built by Darius I (522–486 B.C.) and finished by Xerxes at Persepolis, and the oldest one, that from Pasagardae, dated to the 3rd quarter of the 6th c. B.C. Ashlar. Prismatic-shaped, carved stone block. Barrel vault. Linear vault with a semi-circular section. Centring. Provisional structure to support the single components (voussoirs) of an arch or vault until it is closed and thus support itself. It can also be applied to structures supporting a formwork. Chiaroscuro. Sharp, contrasting shading, drawn by strong light on the moldures, surfaces and volumes of an object. Cloister (or ‘skif ’) Vault. Compound vault in which barrel vaults intersect and form a pyramid-shaped, curbing ceiling. Colonnettes. Small decorative columns with no structural function. Conoid. Three-dimensional surface defined by straight lines stemming from a point (or even a straight line), and resting on a curve that serves as a guideline. Corbel. Cantilevered support, or bracket. Diaphragm Arch. Structural arch placed transversally in a room; intended to reduce the span that is to be covered afterwards with beams or barrel vaults. LAVAN, LAA4_F23-491-537.indd 535 1/11/2008 6:10:18 PM 536 ignacio arce Dog-teeth (also Saw-tooth) cornices. Moldure of Sassanian origin, consisting of a series of triangular elements that can be displayed in a linear design along cornices of springing lines, architraves, etc., or in a circular fashion around the perimeter of an arch. Emplekton. Core filling of a two-face ashlar masonry work, consisting of rubble mixed with mortar. The term was eventually to define the building technique itself. Extrados. The outer (convex) surface of vaults and arches. Formwork. Provisional encasing device to contain and give shape to an element built with a fluid material (concrete, plaster, earth, etc.) before it becomes stiff and self-standing. Groined (or Cross) Vaults. Compound vaults in which barrel vaults intersect, forming ridges called groins. Headers and Stretchers. In masonry, the elements (bricks or ashlars) laid, respectively, across and along the wall. ‘High-flame’ Lime Kilns. Kilns in which the heat required to ‘cook’ the limestone is provided by inefficient fuel (timber) that burns quickly with flame, in a firing chamber placed underneath the upper chamber where the stones to be burnt are placed in a dome-like fashion. Horseshoe Arch. Ultra-semicircular arch in which the curves are carried below the theoretical springing line (the ends of its horizontal diameter), so that the opening at the bottom of the arch is less than its greatest span. Intrados. The inner (concave) surface of vaults and arches. Iwan. Large vaulted hall in which one of the end sides opens onto a courtyard through an arch, which has the same section and span as that of the vault. Prevalent in Parthian, Sassanian and Islamic architecture. Lintelled Structure. Ceiling structure devised with architraves or beams, not arches or vaults. Lintelled Squinch. Squinch built with beams, or architraves, placed in the corners of a room. ‘Low-flame’ Lime Kilns. Kilns in which the heat required to ‘cook’ the limestone is provided by highly efficient fuel (pine cones, olive pits and nut shells) that burns slowly with no flame. They contain a single firing chamber in which combustible materials and stones are placed in alternate layers. Pendentives. Curved wall surfaces, which form a transition between a dome and its supporting structure. Usually, spherical triangles result from the intersection of a half sphere with (4) vertical planes, traced in correspondence with the arches that support the dome, and a (fifth) horizontal plane which corresponds with the springing line of the dome, or drum they support. Pisé (also Tapial ). Building technique used for the construction of walls with rammed earth contained within a wooden and re-usable formwork. Pitched-Brick Vaults. Vaults in which the rows of bricks are laid vertically, or at a slight inclination, leaning against the row previously laid (the very first one leans against the end wall), thus obviating the need for a centring. Pointed Arch (or Two-Centred Arch). Arch defined by two symmetrical sections of circumference, the centres of which are placed separately on the springing line. The distance between the centres defines how acute the pointed arch is. In the first examples, from the Umayyad period, the distance between centres varies from one-tenth to one-seventh of the span of the arch. Later, in the Gothic period, this distance would increase, becoming equal to, or even bigger than, the span of the arch itself, which became increasingly acute. Polylobed Arch. Arch with a compound profile defined by a series of smaller ultrasemi-circular arches, placed alongside the main interior profile of an arch. These smaller, decorative arches (lobes) are usually carved out of the interior surface, but also protrude in some cases. LAVAN, LAA4_F23-491-537.indd 536 1/11/2008 6:10:18 PM umayyad building techniques 537 Pry Marks (or Prise Marks). Holes left on the faces of huge ashlars that were used to place levers, designed to move the upper course ashlars. Sail or Spherical vaults (also Pendentive Domes). Vaults resulting from the intersection of a spherical surface with vertical planes. Also, domes with inner surfaces (intrados) continuous with the surfaces of their pendentives. Squinches. Arches or transitional elements (corbeled architraves, half-cones or conoids) that span the interior corners of a square structure, serving to support a circular or polygonal superstructure, for instance, a dome, or a drum with a dome. Squinch Vault. Vault created by the intersection of 4 or more conical squinches, defined by increasingly wider rings of pitched bricks, which span as much space as required to cover the whole of the room. Stereotomy. Process of cutting solid material, such as stone, into certain volumetric shapes or figures. It is applied to the cutting from cubic blocks of quarry stone into complex elements, such as voussoirs and other elements from arches and vaults. Suspensurae. Elevated floors of heated rooms (caldaria) in Roman baths, built over a heated chamber (hypocaustum) and supported by brick or stone structures ( pilae). Tectonic feature. Structural, load-bearing element. Triconchs. Triple-apsidal hall, usually placed at the end of a basilical/linear space. The term can define the hall or the whole building that contains it. Voussoir. Masonry wedge-shaped element that forms an arch or vault. LAVAN, LAA4_F23-491-537.indd 537 1/11/2008 6:10:18 PM