Professor Robert Bartlett examines the impact of the conquest of Britain and Ireland, and learns how William the Conqueror built scores of castles and cathedrals to impose his control and intimidate the population. The ruler also commissioned the Domesday Book to survey the wealth of the land and raise revenue, and set in motion the linguistic and cultural transformation of England. The Normans blended well in Scotland, but faced fierce opposition in Wales, and promoted divisions in Ireland which some claim still exist to this day