In succeeding years William, earl of Arches, his illegitimate uncle, who had always been faithless and fluctuating from his first entrance on the duchy, rebelled against him; for, even during the siege of Danfrunt, he had unexpectedly stolen away, and had communicated to many persons the secrets of his soul. In consequence of this, William had committed the keeping of his castle to some men, whom he had erroneously deemed faithful; but the earl, with his usual skill in deception, had seduced even these people to his party, by giving them many things, and promising them more. Thus possessed of the fortress, he declared war against his lord. William, with his customary alacrity, contrary to the advice of his friends, laid siege to Arches, declaring publicly, that the miscreants would not dare attempt any thing, if they came into his sight. Nor was his assertion false: for more than three hundred soldiers, who had gone out to plunder and forage, the instant they beheld him, though almost unattended, fled back into their fortifications. Being inclined to settle this business without bloodshed, he fortified a castle in front of Arches, and turned to matters of hostile operation which required deeper attention, because he was aware that the king of France, who had already become adverse to him from some unknown cause, was hastening to the succour of the besieged. He here gave an instance of very laudable forbearance; for though he certainly appeared to have the juster cause, yet he was reluctant to engage with that person, to whom he was bound both by oath and by obligation. He left some of his nobility, however, to repress the impetuosity of the king; who, falling into an ambush laid by their contrivance, had most deservedly to lament Isembard, earl of Ponthieu, who was killed in his sight, and Hugh Bardulf, who was taken prisoner. Not long after, in consequence of his miscarriage, retiring to his beloved France, the earl of Arches, wasted with hunger, and worn to a skeleton, consented to surrender, and was preserved, life and limb, an example of clemency, and a proof of perseverance. During the interval of this siege, the people of the fortress called Moulin, becoming disaffected, at the instigation of one Walter, went over to the king’s side. An active party of soldiers was placed there, under the command of Guy, brother of the earl of Poitou, who diligently attended for some time to his military duties: but on hearing the report of the victory at Arches, he stole away into France, and contributed, by these means, considerably to the glory of the duke.