Chapter XXX, of Cassells Illustrated History of England, Volume 1 page 2

Nothing remained to complete William's satisfaction but the punishment of Ralph de Gael, and he hastened over to Normandy in order to gratify his vengeance on that criminal; but though the contest seemed very unequal between a private nobleman and the King of England, Ralph was so well supported both by the Earl of Brittany and the King of France, that William, after besieging him for some time in Dol, was obliged to abandon the enterprise, and make with those powerful princes a peace, in which Ralph himself was included. England, during his absence, remained in tranquillity, and nothing remarkable occurred, except two ecclesiastical synods, which were summoned, one at London, another at Winchester. In one of these the precedency among the episcopal sees was settled, and the seat of some of them was removed from small villages to the most considerable town within the diocese.