William of Normandy claimed that he was the rightful heir to the King of England, Edward the Confessor. When Edward died in January 1066, two other powerful men, Harold Godwinson and Harald Hardrada, also claimed they were the rightful heirs to the English crown. After three major battles in 1066, Duke William of Normandy was crowned King William I of England.
1066 was the beginning rather than the end of the Norman conquest of England. William had to fight hard to protect his kingdom from English rebels and the Welsh and Danish armies that supported them. A combination of brutal suppression, and changes to the Church and the justice system gradually strengthened Norman control over England.