William the Conqueror eldest son. William was the son of the unmarried Robert I, Duke of Normandy, by Robert's mistress Herleva. His illegitimate status and his youth caused some difficulties for him after he succeeded his father, as did the anarchy that plagued the first years of his rule. During his childhood and adolescence, members of the Norman aristocracy battled each other, both for control of the child duke and for their own ends. In 1047 William was able to quash a rebellion and begin to establish his authority over the duchy, a process that was not complete until about 1060. His marriage
William IV, Grand Duke of Luxembourg William IV, Grand Duke of Luxembourg William IV (William Alexander; "French: Guillaume Alexandre"; 22 April 1852 – 25 February 1912) reigned as the Grand Duke of Luxembourg from 17 November 1905 until his death. He succeeded his father, Adolphe. William was a Protestant, the religion of the House of Nassau. He married Princess Marie Anne of Portugal, believing that a Roman Catholic country ought to have a Roman Catholic monarch. Thus his heirs have been Catholic. At the death of his uncle, Prince Nikolaus-Wilhelm in 1905, the only other legitimate male in the House of Nassau-Weilburg was William's cousin, Georg