The "Spanish Road" was a military supply/trade route used from 1567–1620, which stretched from Northern Italy to the Low Countries. It crossed through relatively neutral territory, and was therefore Europe's most preferred military route. In the days of its use it was known in French as "le chemin des Espagnols".

Soldiers were able to march the 1,000 km (620 mi) from Milan to Flanders an average of 23 km (14 mi) a day. Sea transport was much faster, able to cover about 200 kilometers (120 mi) a day, but was highly exposed to storms and enemy attacks. For large groups, overland communication was more reliable, allowing the Spanish to send over 123,000 men compared to only 17,600 by sea, between 1567 and 1620.

Necessity

The conflict between the Spanish King Philip II and the Dutch rebels in the Spanish-ruled Habsburg Netherlands, culminating in the Eighty Years' War, symbolized the prominent European power struggle of the 16th century between Catholics and Protestants. In 1550, the wars had stretched Spain's finances thin. 1566 was known as the "Year of Hunger" or "Year of Wonders". When social, political and religious unrest culminated in the Compromise of Nobles and the Beeldenstorm, apparently endangering the government of Philip's Regent in Brussels, Margaret of Parma, Spanish troops under the Duke of Alba were dispatched to restore order and punish the perceived insurrectionists. Those troops could at the time not be transported by sea and Philip was therefore forced to find a route to move troops from his garrisons in Spanish Italy overland to his Netherlands domains, crossing neutral territory. The Spanish Road was surveyed and mapped out in 1566, and Alba used it in July 1567.