The ruler of the Normans , William of Normandy , claimed he was the heir to the English throne as his cousin , Edward the Confessor , had promised him the throne but changed his mind on his deathbed . Some sources say that Edward had verbally promised the throne to his cousin , William , the Duke of Normandy , but decided on his deathbed to give it to Harold . While Edward the Confessor had an English great-nephew who might have qualified as his successor , he was deemed too young .