Canterbury city walls are a sequence of defensive walls built around the city of Canterbury in Kent, England. The first city walls were built by the Romans, probably between 270 and 280 AD. These walls were constructed from stone on top of an earth bank, and protected by a ditch and wall towers. At least five gates were placed into the walls, linked to the network of Roman roads across the region. With the collapse of Roman Britain, Canterbury went into decline but the walls remained, and may have influenced the decision of Augustine to settle in the city at the end of the 6th century. The Anglo-Saxons retained the defensive walls, building chapels over most of the gates and using them to defend Canterbury against Viking incursions.The Norman invaders of the 11th century took the city without resistance, and by the 12th century the walls were ill-maintained and of little military value. Fears of a French invasion during the Hundred Years' War led to an enquiry into Canterbury's defences in 1363. The decision was taken to restore the city walls and for around the next thirty years the old Roman defences were freshly rebuilt in stone, incorporating the older walls where they still remained. 24 towers were constructed around the circuit, and over the coming years many of the gatehouses were rebuilt in stone and brick, defended by some of the first batteries of guns in England. Parts of the wall were deliberately damaged by Parliament during the English Civil War of the 17th century and the doors to the city's gates burnt; with the restoration of Charles II in 1660, new doors were reinstalled.