Strongly fortified residence of stone or brick build around a square or rectangular courtyard known as a ‘ward’. The outer walls formed the defensive line of ‘enceinte’ and towers would usually be placed at the corners and sometimes in intermediate positions too. Some very strongly fortified castles of this class have an additional wall set a short distance out from the main enceinte and concentric with it, the area between the two walls being termed the outer ward or outer bailey. Moats, either wet or dry, often encircle the walls. Accommodation within the castle was provided in the towers or in buildings set against the walls and opening into the ward. Quadrangular castles were the strongly defended residences of the king or a lord, situated for offensive as well as defensive operations, and often acting as an administrative centre. Most were constructed in the 14th century ad, although they continued to be built and used through into the early 15th century. Amongst the best examples in Britain are Bodiam, Sussex, and Castle Bolton, Yorkshire.