William I (circa 1028 â€“ 9 September 1087), also known as William the Conqueror (Guillaume le ConquÃ©rant), was the first Norman King of England from Christmas 1066 until his death. He was also Duke of Normandy from 3 July 1035 until his death, under the name William II. Before his conquest of England, he was known as William the Bastard because of the illegitimacy of his birth.
To press his claim to the English crown, William invaded England in 1066, leading an army of Normans, Bretons, Flemings, and Frenchmen (from Paris and ÃŽle-de-France) to victory over the English forces of King Harold Godwinson at the Battle of Hastings, and suppressed subsequent English revolts in what has become known as the Norman Conquest. His reign, which brought Norman-French culture to England, had an impact on the subsequent course of England in the Middle Ages. The details of that impact and the extent of the changes have been debated by scholars for centuries. In addition to the obvious change of ruler, his reign also saw a programme of building and fortification, changes to the English language, a shift in the upper levels of society and the church, and adoption of some aspects of continental church reform.