Normandy and the neighbouring principalities

The frontiers of ducal Normandy were established according to the strength at its disposal, but they were continually challenged by its neighbours. When William asserted his power over Normandy the Count of Anjou, Geoffrey Martel (1040-1060) emerged on the political chessboard. The rivalry between the two princes was fuelled by the policies of King Henry I of France who alternately played each of his vassals off against the other in the hope of containing their power.

Between 1049 and 1051 the Duke of Normandy and the Count of Anjou were brought into conflict over the control of the Maine region. The King of France assisted by William laid siege to the castle of Mouliherne (Maine-et-Loire), Geoffrey Martel to Le Mans and the Norman towns of Alençon and Domfront. These operations culminated in the victory of the Duke of Normandy. The region of Passais, around Domfront, was annexed.

The King of France immediately reversed his alliance to the advantage of the Count of Anjou and the rebellious Norman barons opposed to the authority of the Duke. In 1054 two great armies attacked Normandy, one in the south and one in the north. One of these was led by Eudes, the brother of the King of France. His camp was taken by surprise and massacred at Mortemer. A new offensive in 1057 was led up the Orne valley. This was intercepted at the ford of Varaville near Caen. The King of France had to retreat before the Duke of Normandy.

The Duke of Normandy now had his hands free to pursue the conquest of Maine which he had inherited on the death of Count Herbert II, who had taken refuge with him. In 1063 William took Le Mans and had the title of Count of Maine bestowed upon his young son Robert Curthose. Finally, in 1064 William was able to intervene in Brittany in the conflict between Conan II and Eudes de Penthièvre. During an expedition which is portrayed in the Bayeux Tapestry, the Duke liberated Dol from its besiegers, took Dinan and re-established his authority over Mont-Saint-Michel.

He was accompanied by an Anglo-Saxon lord who conducted himself as a perfect companion at arms: Harold Godwinson.