They are armed, they are getting ready; to tarry is death." William did not hesitate; he got up, ran to the stables, saddled his horse with his own hands, started off, followed a road called to this day the duke's way, and reached Falaise as a place of safety.

There news came to him that the conspiracy was taking the form of insurrection, and that the rebels were seizing his domains.

William showed no more hesitation at Falaise than at Valognes; he started off at once, repaired to Poissy, where Henry I., king of France, was then residing, and claimed, as vassal, the help of his suzerain against traitors.

Henry, who himself was brave, was touched by this bold confidence, and promised his young vassal effectual support.
William returned to Normandy, summoned his lieges, and took the field promptly.

King Henry joined him at Argence, with a body of three thousand men-at-arms, and a battle took place on the 10th of August, 1047, at Val des Dunes, three leagues from Caen.