Territorial evolution of France face up to the formidable challenge with which they were presented. The Duke of Normandy William the Conqueror became King of England in 1066 through his victory at Hastings over the Saxons. On the extinction of his male line of descent, his heir was the Duke of Anjou, Henry Plantagenet, grandson by his mother of Henry I of England. Two months before he ascended to the English throne, as Henry II, he married Eleanor, Duchess of Aquitaine, the richest heiress in the French kingdom and ex-wife of the King of France. The kings of France nevertheless, held some trump cards:
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.