As to the date at which the original Roman wall was built, widely different opinions are held. It was possibly built in the latter part of the first century A.D., presumably as a result of the destruction of the undefended town by Boadicea and her rebels in the year 61.
But it could have been built in the following century and almost certainly was redeveloped continually until the Romans withdrew from Britain in 410.
Later in the Roman occupation, at least one of the Roman gates (Newgate) was rebuilt, at a time when the accumulation of debris had raised the ground-level several feet above that at which the town-wall had been built.
At various moments also in the latter part of the period a wall was built or rebuilt along the river front, and two sets of semicircular bastions were added to the defences.
Lacing-courses of brick were again used, hut otherwise the construction of these works differed from the old; in particular, the river wall and the series of bastions east of the Walbrook were built partly of architectural and sculptured fragments taken from former buildings and from the cemeteries of the Roman town, just as were the fortifications of the Gallic cities after the destructive German invasion of Gaul in 276.