King William I, also known as William the Conqueror, was the first Norman King of England, reigning from 1066 until his death in 1087. He was born in 1028 in Falaise, Normandy and became Duke of Normandy in 1035. William is best known for leading the successful invasion of England in 1066, which began with the famous Battle of Hastings. His reign marked significant changes in English society, including the introduction of Norman culture and the feudal system. William commissioned the Domesday Book, a comprehensive survey of his new kingdom, which provided valuable information about land ownership and resources. His rule laid the foundation for the future development of England.