William the Conqueror, originally known as William I of England, was a Norman duke who became the first Norman king of England after his victory at the Battle of Hastings in 1066. He was born in 1028 in Falaise, Normandy and was the illegitimate son of the Duke of Normandy. His claim to the English throne was based on a promise made by Edward the Confessor, the previous king. After his conquest, William implemented significant changes in England, including the introduction of the feudal system and the commissioning of the Domesday Book, a survey of his new kingdom. His reign marked the beginning of a new era in English history, blending Norman and Anglo-Saxon cultures.