Norman Conquest, period in English history following the defeat (1066) of King Harold of England by William, duke of Normandy, who became William I of England. The conquest was formerly thought to have brought about broad changes in all phases of English life. More recently historians have stressed the continuity of English law, institutions, and customs, but the subject remains one of controversy. The initial military conquest of England was quick and brutal. The members of the Anglo-Saxon upper class who were not killed in the battle of Hastings were almost all involved in the rebellion from 1068 to 1070 and were either killed or deprived of their lands. Thus a Norman aristocracy was superimposed on the English, and the new elite brought with it Norman feudal customs (see feudalism), which were reinforced by the need for cohesion and mutual military support among the fairly small group of conquerors. Thus the rebellions among the Norman barons were minor and short-lived, the interests of stability being paramount. To consolidate his position William used the existing Anglo-Saxon administrative system, which functioned as part of a centralized monarchical tradition. It was this tradition, as adapted by the Normans, that gave English feudalism its uniquely cohesive nature. There was little change in the administrative and judicial systems during the Norman period (usually defined as ending with the accession of the Plantagenet Henry II in 1154) and later developments were not in the nature of Norman superimpositions. William I's archbishop of Canterbury, Lanfranc, established a separate system of canon law courts, effectively asserted the supremacy of his archdiocese, and brought the English church into closer contact with developments in Europe, particularly with the reforms of Pope Gregory VII. The Norman kings, however, successfully resisted papal encroachment on their control over episcopal appointments. The period saw many churches and castles built, the latter chiefly on the south and east coasts and on the Welsh and Scottish borders (see Norman architecture). Norman French became the language of the court and upper classes, and of literature, and had great effect on the development of the English language.
See D. J. A. Matthew, The Norman Conquest (1966); D. C. Douglas, The Norman Achievement, 1050–1100 (1969); F. M. Stenton, The First Century of English Feudalism, 1066–1166 (2d ed. 1961) and Anglo-Saxon England (3d ed. 1971); J. LePatourel, Feudal Empires: Norman and Plantagenet (1984).