London Wall - Construction of The Roman Wall

Construction of The Roman Wall

The wall appears to have been built in the late 2nd or early 3rd century, certainly between 190 and 225, and probably between 200 and 220. This was around 80 years after the construction in 120 of the city's fort, whose north and west walls were thickened and doubled in height to form part of the new city wall. It continued to be developed until at least the end of the 4th century, making it among the last major building projects undertaken by the Romans before the Roman departure from Britain in 410.

Although the exact reason for the wall's construction is unknown, it may have been connected to the invasion of northern Britain by Picts who overran Hadrian's Wall in the 180s. Alternatively, many historians link the building of London Wall with the political crisis that had emerged in the 190s when two men—Septimius Severus, and the governor of Britain Clodius Albinus—both claimed the right to succession as Emperor. The wall may have been constructed on the orders of Albinus in the 190s, who, in a power struggle with his rival, may have felt the need to protect his capital. Septimius eventually defeated his rival in 197.

Along with Hadrian's Wall and the road network, the London Wall was one of the largest construction projects carried out in Roman Britain. The wall was constructed largely from Kentish ragstone brought by water from Maidstone. It has been calculated that some 1,300 barge journeys would have been required to transport the 85,000 tons of stone from Kent. Once built, the wall was nearly 3 miles (5 kilometres) long, enclosed an area of about 330 acres (130 ha), and was 6 to 9 feet (2 to 3 m) wide and about 20 feet (6 m) high. It had a ditch or fossa in front of the outer wall, measuring some 6 feet (2 m) deep by between 9 and 15 feet (3 to 5 m) wide. It included a number of bastions (at least twenty-two) spaced about 70 yards (64 m) apart, on the eastern section of the wall.

The economic stimulus provided by the wall and Septimius's campaigns of conquest in Scotland appear to have revived Londinium's fortunes somewhat in the early third century.