Summary : The line of the Roman walls formed the core for the Medieval city defences; the upper Roman town became the outer bailey for the castle, `The Bail'. The Roman walls were first built in the late 1st century around the Colonia, the walls around the upper town replacing the earth and timber defences of the preceding legionary fortress. Several fragments of the wall remain, including parts of the north, east, and south gates of the upper town, while the west gate was exposed in the castle mound in 1836, but collapsed and was reburied. The south gate of the lower town has also been found by excavation. Throughout the Middle Ages the Roman defences continued in use, the ditch being redug, several Roman gates being reutilised and repaired. |