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 Ernest, Duke of Saxe-Weimar William Ernest, Duke of Saxe-Weimar William Ernest, Duke of Saxe-Weimar (19 October 1662 – 26 August 1728) was a duke of Saxe-Weimar. He was born in Weimar, the eldest son of Johann Ernst II, Duke of Saxe-Weimar and Princess Christine Elisabeth of Schleswig-Holstein-Sonderburg. When his father died in 1683, he succeeded him as duke; however, he was compelled to rule jointly with his younger brother Johann Ernst III. Because John Ernest III was alcoholic, William Ernest took full control of the government of the duchy and permitted John Ernest the nominal title of co-duke ("Mitherr") until his death in 1707.