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 I, Duke of Bavaria William I, Duke of Bavaria William I, Duke of Bavaria-Straubing (Frankfurt am Main, 12 May 1330 – 15 April 1389, Le Quesnoy), was the second son of the emperor Louis IV the Bavarian from his second wife Margaret of Holland and Hainaut. He was also known as William V, Count of Holland, as William III, Count of Hainaut and as William IV, Count of Zeeland. In 1345 William's father was conferring Hainaut, Holland, Zeeland and Friesland upon his wife Margaret, and shortly later also upon their son William. After his father's death in 1347 William ruled Bavaria, Holland and Hainaut