The division of William the Conqueror's lands into two parts presented a dilemma for those nobles who held land on both sides of the English Channel. Since the younger William and his brother Robert were natural rivals, these nobles worried that they could not hope to please both of their lords, and thus ran the risk of losing the favour of one ruler or the other, or both. The only solution, as they saw it, was to unite England and Normandy once more under one ruler. The pursuit of this aim led them to revolt against William in favour of Robert, under the leadership of the powerful Bishop Odo of Bayeux, who was a half-brother of William the Conqueror.