Henry I of France whose death Henry was left to deal with his rebel sibling. In 1032, he placated his brother by giving him the duchy of Burgundy which his father had given him in 1016. In an early strategic move, Henry came to the rescue of his very young nephew-in-law, the newly appointed Duke William of Normandy (who would go on to become William the Conqueror), to suppress a revolt by William's vassals. In 1047, Henry secured the dukedom for William in their decisive victory over the vassals at the Battle of Val-ès-Dunes near Caen; however, Henry would later support the barons against
William the Conqueror in either late 1039 or October 1040, Gilbert of Brionne took charge of William. Gilbert was killed within months, and another guardian, Turchetil, was also killed around the time of Gilbert's death. Yet another guardian, Osbern, was slain in the early 1040s in William's chamber while the duke slept. It was said that Walter, William's maternal uncle, was occasionally forced to hide the young duke in the houses of peasants, although this story may be an embellishment by Orderic Vitalis. The historian Eleanor Searle speculates that William was raised with the three cousins who later became important in his career