William the Duke of Normandy invaded England in 1066 after the death of King Edward the Confessor left the English throne disputed. Harold Godwinson seized the throne but faced invasions from Norway and Normandy. At the Battle of Hastings on October 14, 1066, William defeated and killed Harold, establishing Norman rule over England and crowning himself as King William I. The Norman conquest brought significant changes including replacing Anglo-Saxon culture and language with Norman French and introducing the feudal system to England.