William of Talou was the son of duke Richard II of Normandy and Papia from Envermeu. His brother was Mauger, who became archbishop of Rouen in 1037. Their elder half-brothers were dukes of Normandy, Richard III from 1026 to 1027, and Robert I, Duke of Normandy from (1027 to 1035), the father of William the Conqueror.