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, Duke of Brunswick the ruling duke permanently. William left most government business to his ministers, and he spent most of his time outside of his state at his possessions in Oels. While William joined the Prussian-led North German Confederation in 1866, his relationship to Prussia was strained, since Prussia refused to recognize Ernest Augustus, Crown Prince of Hanover, his nearest male-line relative, as his heir, because of the Duke of Cumberland's claim to the throne of Hanover. William died in 1884; he passed on his private possessions to the Duke of Cumberland. His death caused a constitutional crisis for Brunswick that lasted until