William I, Count of Eu (978-after 1057), illegitimate son of Richard I, Duke of Normandy. Count of Eu and Count of Hiémois. William succeeded his nephew as Count of Eu and Hiémois after his murder in 1040. [Some believe that William and Geoffrey are both the sons of Richard's mistress Gunnora de Crepon, but Dudo of Saint-Quentin disputes this.]
William rebelled against his half-brother Richard II, Duke of Normandy, and was captured by Raoul d’Ivry and imprisoned by Turquetil of Harcourt, former governor of William the Conqueror.. He escaped five years later and, eventually, was pardoned by Richard and given leave to marry into the Harcourt family.
William married Lesceline, daughter of Turquetil. William and Lesceline had three children:
William’s son and namesake succeeded him a count of Eu.
Waters, Edmund C., The Counts of Eu, Sometime Lords of the Honour of Tickhill, The Yorkshire Archaeological and Topographical Journal, No. 9, 1886
Douglas, David, The Earliest Norman Counts, The English Historical Review, vol. 61, no 240, 1946
Bauduin, Pierre, La première Normandie: Sur les frontières de la haute Normandie : Identité et Construction d'une Principauté, Caen, Presses universitaires de Caen, 2006.