Castles developed first in France in the 10th cent. The first castles in England were built in Edward the Confessor's reign by his Norman followers, and were strongly resented by the English, as foreign imports. Lordly residences in late Saxon England appear to have been enclosed with a palisade and a ditch, but the defences were slight. Castles were an introduction into England and a direct consequence of the Norman invasion of 1066.
Orderic Vitalis, a Norman historian, said that the English fought bravely but lost because they lacked castles. William secured his first landing in England with a wooden castle, and on entering London, after the battle of Hastings, one of his first acts was to order the creation of a castle to control the city: the Tower of London. William used castles to secure his new kingdom; the nobles to whom he granted estates did the same in taking control of their new lands. The castles built immediately after the Conquest, whether by the king or his followers, were generally rapidly constructed of earth and timber. In form, they were either a fortified enclosure surrounded by a ditch (known as a ringwork) or a motte and bailey, that is an earth mound topped with a fortification and surrounded by a ditch connected to a further lower fortified enclosure. Large castles like Windsor, Dover, or Richmond seem to have been conceived from the first as residences as well as fortresses. The White Tower built by William I to subdue London incorporated two large suites of rooms, a grand chapel, and extensive storage space. During the Conquest all Norman barons, great or small, seem to have built castles; however, the wooden fortresses were not very durable and their owners were soon forced to decide whether they should be replaced in stone. Further, the castle's importance in warfare meant that its design was constantly being refined so that to maintain its military efficiency meant a constant outlay. Many smaller landowners ceased to be castle owners, preferring instead a fortified manor house. Castles became the prerogative of the wealthy baronage and the crown. Thus the castles which are notable monuments today are those which were rebuilt and updated in the 12th cent. and later. Amongst the most developed examples in Britain are the castles built for Edward I in north Wales, for example, Conwy, Caernarfon, and Harlech. Despite the introduction of gunpowder, castles retained their importance. Late examples, such as Raglan (Monmouthshire), were designed to include cannon as part of their defences. Castles were again important in the English Civil War, when large numbers were refortified and held for the king. In recognition of the part that castles had played in the war, the majority of surviving buildings were slighted by the victorious parliamentarians.