The youth of Duke William (1035-1047)

This third minor as a Duke of Normandy was the most dangerous of all for the Duchy. Before his death, Duke Robert had required an oath of loyalty to his son William born of his concubine Herleve (Arlette), but the great lords of the Duchy, originating from the ducal family, disputed the validity of his regency. Those close to the young duke were assassinated in turn: firstly Gilbert de Brionne, his tutor, then Turold, his preceptor and finally the seneschal Osbern de Crépon whose throat was cut before William's very eyes.

With Normandy open to anarchy, it fell victim to attacks from the King of France and the Duke of Brittany. The traditionally rebellious regions also rose up. William had to lay siege to his castle of Falaise which was taken by the Viscount of Hiémois (1042).

The troubles triggered a cycle of private wars which the justice of the Duke as a minor was powerless to stop. The most dangerous were those which concerned the family of Bellême, whose domains touched Maine where Normans and Angevins were in competition.

Barons fighting each other or against the authority of the Duke were based in a network of small fortresses of wood and earth, castle mottes, in violation of the right to hold fortresses which was reserved for the Duke. With profits of their private wars behind them they did not propose to return to the fold of the authority of the young William.

A group of minor lords of the west of Normandy, supported by the Viscounts of Cotentin and Bayeux, theoretical representatives of ducal authority, and higher ranking barons, Guy of Brionne, Bishop of Bayeux, and possibly the Abbot of Mont-Saint-Michel, plotted together against the Duke. An attempted murder was organised at a hunting meeting at Valognes. Having been alerted of this, William took flight alone on horseback from Valognes across the bay of Veys, via Ryes in Bessin and sought refuge in his castle at Falaise.