In the Middle Ages the major European towns were enclosed by great ditches and embankments surmounted by a wall. The City of London was thus enclosed on the north bank of the Thames. Very little of London's wall survives, but its outline is known from early maps and is commemorated by various place‐names. Between the 11th and the 16th century England and Wales had about 230 towns that possessed some defences, whether earthwork or masonry circuits or gates alone, and Scotland about 25, but these were limited in scale compared with those in mainland Europe and most towns had none at all. See Oliver Creighton, ‘Town Defences and the Making of Urban Landscapes’, in Mark Gardiner and Stephen Rippon (eds), Medieval Landscapes (2007). Tracing the outline of a town wall by archaeological and historical methods is usually a local exercise in cooperation. The finest surviving town walls in Britain are those of York, Chester, Canterbury, and Conwy. Excavations at York have shown how the previous walls of the Romans, Vikings, and Normans underlie the present walls, which date largely from the 13th and early 14th centuries, though stretches have been substantially repaired in the 18th and 19th centuries. The walls were defended by four great bars, six posterns, and 44 towers. The bars, which formed the principal entrances to the town, remain largely intact, though only that at Walmgate retains its barbican, the rest having been destroyed in the early 19th century to facilitate the movement of traffic. Important dignitaries were received by the mayor and corporation at one of the bars, and the heads of executed traitors were displayed from the battlements. Each bar had a portcullis, which was closed at night‐time. The walls acted as an effective barrier against undesirable migrants and symbolized the importance of a town. See Barbara Wilson and Frances Mee, The City Walls and Castles of York (2005).
Most towns did not update their defences in the 16th century, but good examples of the improved techniques imported from Italy can be seen at Portsmouth and Berwick‐upon‐Tweed, where the defence system was revised at every new crisis. See I. MacIvor, ‘The Elizabethan Fortifications of Berwick‐on‐Tweed’, Antiquaries Journal, 45 (1965), and A. D. Saunders, ‘Hampshire Coastal Defences since the Introduction of Artillery’, Archaeological Journal, 123 (1966). John Speed's maps show that many towns were still largely contained within their medieval limits in the early 17th century. See also suburbs.