870

870 in various calendars
Gregorian calendar	870; DCCCLXX
Ab urbe condita	1623
Armenian calendar	319; ԹՎ ՅԺԹ
Assyrian calendar	5620
Balinese saka calendar	791–792
Bengali calendar	277
Berber calendar	1820
Buddhist calendar	1414
Burmese calendar	232
Byzantine calendar	6378–6379
Chinese calendar	己丑年 (Earth Ox); 3567 or 3360; — to —; 庚寅年 (Metal Tiger); 3568 or 3361
Coptic calendar	586–587
Discordian calendar	2036
Ethiopian calendar	862–863
Hebrew calendar	4630–4631
Hindu calendars
- Vikram Samvat	926–927
- Shaka Samvat	791–792
- Kali Yuga	3970–3971
Holocene calendar	10870
Iranian calendar	248–249
Islamic calendar	256–257
Japanese calendar	Jōgan 12; (貞観１２年)
Javanese calendar	767–768
Julian calendar	870; DCCCLXX
Korean calendar	3203
Minguo calendar	1042 before ROC; 民前1042年
Nanakshahi calendar	−598
Seleucid era	1181/1182 AG
Thai solar calendar	1412–1413
Tibetan calendar	阴土牛年; (female Earth-Ox); 996 or 615 or −157; — to —; 阳金虎年; (male Iron-Tiger); 997 or 616 or −156

Millennium:	1st millennium
Centuries:	8th century; 9th century ; 10th century;
Decades:	850s; 860s; 870s ; 880s; 890s;
Years:	867; 868; 869; 870 ; 871; 872; 873;

Year 870 (DCCCLXX) was a common year starting on Sunday (link will display the full calendar) of the Julian calendar, the 870th year of the Common Era (CE) and Anno Domini (AD) designations, the 870th year of the 1st millennium, the 70th year of the 9th century, and the 1st year of the 870s decade.

Events

August 8 – Treaty of Meerssen: King Louis the German forces his half-brother Charles the Bald to accept a peace treaty, which partitions the Middle Frankish Kingdom into two larger east and west divisions. Louis receives most of Austrasia (which evolves into the Kingdom of Germany), and Charles receives territory in Lower Burgundy (which evolves into the Kingdom of France). However, large parts of the Frisian coast are under Viking control.
Charles the Bald marries Richilde of Provence, after the death of his first wife, Ermentrude of Orleans. He intends to secure his rule in Lotharingia through the powerful Bosonid family and the connection to Teutberga, widow-queen of Lothair II.^[1]
Rastislav, ruler (knyaz) of Great Moravia, dies in prison after he is condemned to death for treason, by Louis the German. He is succeeded by his nephew Svatopluk I, who becomes a vassal of the East Frankish Kingdom.
Bořivoj I, duke of Bohemia, makes Levý Hradec (modern Czech Republic) his residence. Around this time Prague Castle is founded (approximate date).
Wilfred the Hairy, a Frankish nobleman, becomes count of Urgell and Cerdanya (modern-day Catalonia).

Autumn – The Great Heathen Army, led by Ivar the Boneless and Ubba, invades East Anglia and plunders Peterborough. King Edmund the Martyr is captured, tortured, beaten and used for archery practice (or 869).
The Danes, led by Ivar the Boneless and King Olaf of the Dublin Vikings, besiege Dumbarton in Scotland, the capital of King Artgal of Stratchlyde. After a siege of four months, the citadel is captured and destroyed.^[2]
The Danes, led by Halfdan Ragnarsson and Bagsecg, invade Wessex and take the royal estate at Reading (Berkshire), which Halfdan makes his headquarters. A naval Viking contingent sails up the Thames River.^[3]
December 31 – Battle of Englefield: The Vikings clash with ealdorman Æthelwulf of Berkshire. The invaders are driven back to Reading; many of the Danes (including one of the earls named Sidrac) are killed.

January 29 – Anarchy at Samarra: The rebel Salih ibn Wasif is hunted down and killed in Abbasid Samarra by troops of Musa ibn Bugha al-Kabir.
June 21 – Caliph Al-Muhtadi is deposed and killed by the Turks, after a brief reign. He is succeeded by Al-Mu'tamid (son of the late Al-Mutawakkil) as ruler of the Abbasid Caliphate, who moves his court to Baghdad. End of the Anarchy at Samarra.
Byzantine–Arab War: A Muslim expeditionary force, led by Halaf al-Hadim, Arab governor of Sicily, conquers Malta. He is welcomed by the local Christian inhabitants as liberator of the agonizing Byzantine yoke. The Muslims sign a treaty with the Christians to live in peace after liberating the island from the Byzantines.
The Zanj Rebellion: The Zanj (black slaves from East Africa) capture the Abbasid seaport of Al-Ubdullah at the Persian Gulf, and cut off communications with Basra (modern Iraq).

February 28 – The Fourth Council of Constantinople ends. The Bulgarians are granted an autocephalous archbishopric. with its seat in the capital of Pliska.

^ Monumenta Germanica Historica, tomus I: Annales Lobienses, anno 855, p. 232.
^ MacQuarrie (2013), pp. 12–13.
^ Paul Hill (2009). The Viking Wars of Alfred the Great, p. 37. ISBN 978-1-59416-087-5.
^ Hartley, Cathy (2003). A Historical Dictionary of British Women. Psychology Press. p. 7. ISBN 9781857432282.