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 Younger, Duke of Brunswick-Lüneburg William the Younger, Duke of Brunswick-Lüneburg Wilhelm (4 July 1535 – 20 August 1592), called William the Younger (""), was Duke of Brunswick-Lüneburg and Prince of Lüneburg from 1559 until his death. Until 1569 he ruled together with his brother, Henry of Dannenberg. William was the son of Ernest I, Duke of Brunswick-Lüneburg. On 12 October 1561 he married Dorothea of Denmark (29 June 1546 Kolding–6 January 1617 Winsen), daughter of Christian III of Denmark and Dorothea of Saxe-Lauenburg. In 1582, William began suffering from fits of insanity. These fits caused his wife to flee him in 1584 for her