Final answer:
Duke William of Normandy defeated Harold at the Battle of Hastings in 1066, starting the Norman Conquest and leading to William's coronation as the King of England.
Step-by-step explanation:
Duke William invaded England in September of 1066 and defeated Harold at the Battle of Hastings. This pivotal event is commemorated in the famous Bayeux Tapestry, which illustrates the events leading up to the Norman Conquest of England. The tapestry includes scenes of the decisive battle where William, the Duke of Normandy who would become known as William the Conqueror, overcame Harold, the last Anglo-Saxon king of England. This marked the beginning of Norman rule and significant changes in English society, including the architecture exemplified by Durham Cathedral and shifts in governance and land ownership.
William's claim to the throne was strengthened by an alleged feudal pledge of fealty from Harold Godwinson made before the battle. The victory at Hastings and the subsequent coronation solidified William's position as the Norman King of England. King William's War, although relevant to the name William and an invasion led by a man named William, occurred much later and pertains to a different historical William—William of Orange—and his endeavors during 1688-1697.