William the Conqueror defeated King Harold at the Battle of Hastings in 1066 and established Norman rule over England. He introduced feudalism, where land was exchanged for military service to the king. Over time, the feudal system declined as towns grew and the Black Death reduced the peasant population. Conflict between the monarchy and nobility, as well as between royal houses, led to the War of the Roses and the establishment of the Tudor dynasty by the late 15th century, marking the end of the medieval period in England.