Antonine Wall: Defensive fortification in Roman Britain

The Roman emperor Antoninus Pius built the wall to control barbarians: the ancient Britons to the north of the wall, in Caledonia. The wall is now in Scotland, and runs between the Firth of Forth and the Firth of Clyde in the modern Scottish Lowlands. When the Romans built the wall, it was the northern border of the Roman Empire.

The Roman legions (armies) of the governor of Roman Britain, Lollius Urbicus, built the wall for the emperor between 139 and 142. The wall was about 59 kilometres (37 miles) long. Its foundations were made of stone and was between 4.5 metres (15 feet) and 5 metres (16 feet) wide. The wall itself was made of turf. In front of the wall (on the northern side) was a ditch. The ditch was 7 metres (23 feet) away from the wall. The ditch was at least 3.6 metres (12 feet) deep and was nearly 12 metres (39 feet) wide in places. The Romans used the wall until after 158. The last Romans went away from the wall in around 163. After that, the wall fell into ruins slowly.

The Antonine Wall is part of the UNESCO World Heritage Site called Frontiers of the Roman Empire. It shares this listing with Hadrian's Wall in England and the German fortifications known as the Limes Germanicus. The barrier was the second of two "great walls" created by the Romans in Great Britain. Its ruins are less visible than the better known Hadrian's Wall to the south.

Construction began in AD 142 at the order of emperor Antoninus Pius, and took about twelve years to complete. Pressure from the Caledonians may have led Antoninus Pius to send the empire's troops farther north. The wall was protected by sixteen forts with a number of small fortlets between them; troop movement was facilitated by a road linking all the sites known as the Military Way. The soldiers who built the wall commemorated the construction and their struggles with the barbarians in a number of decorative slabs, twenty of which still survive.

Despite this good start, the wall was abandoned after only twenty years. The garrisons were sent back to Hadrian's Wall. In 208 the emperor Septimius Severus re-established legions at the wall and ordered repairs. This has led to the wall being referred to as the Severan Wall. However, this occupation ended only a few years later, and the wall was never fortified again. Most of the wall and its associated fortifications have been destroyed over time, but some remains are still visible. Many of these have come under the care of Historic Scotland and the UNESCO World Heritage Site Committee. Most of the wall is private property.