At the conclusion of the treaty of Gouleton in May 1200 Arthur, after doing homage to his uncle for Britanny, had been by him restored to the guardianship of the French king.[372] The death of the boy’s mother in September 1201[373] left him more than ever exposed to Philip’s influence; and it was no doubt as a measure of precaution, in view of the approaching strife between the kings, that John on March 27, 1202--two days after his meeting with Philip at Gouleton--summoned his “beloved nephew Arthur” to come and “do right” to him at Argentan at the octave of Easter.[374] The summons probably met with no more obedience than did Philip’s summons to John; and before the end of April Philip had bound Arthur securely to his side by promising him the hand of his infant daughter Mary.[375] This promise was ratified by a formal betrothal at Gournay, after the capture of that place by the French; at the same time Philip made Arthur a knight, and gave him the investiture of all the Angevin dominions except Normandy.[376] Towards the end of July Philip despatched Arthur, with a force of two hundred French knights, to join the Lusignans in an attack on Poitou. The barons of Britanny and of Berry had been summoned to meet him at Tours; but the only allies who did meet him there were three of the Lusignans and Savaric de Mauléon, with some three hundred knights. Overruling the caution of the boy duke, who wished to wait for reinforcements from his own duchy, the impetuous southerners urged an immediate attack upon Mirebeau, their object being to capture Queen Eleanor, who was known to be there,[377] and whom they rightly regarded as the mainstay of John’s power in Aquitaine. Eleanor, however, became aware of their project in time to despatch a letter to her son, begging him to come to her rescue. He was already moving southward when her courier met him on July 30 as he was approaching Le Mans. By marching day and night he and his troops covered the whole distance between Le Mans and Mirebeau--eighty miles at the least--in forty-eight hours, and appeared on August 1 before the besieged castle.[378] The enemies had already taken the outer ward and thrown down all the gates save one, deeming their own valour a sufficient safeguard against John’s expected attack.[379] So great was their self-confidence that they even marched out to meet him. Like most of those who at one time or another fought against John, they underrated the latent capacities of their adversary. They were driven back into the castle, hotly pursued by his troops, who under the guidance of William des Roches forced their way in after the fugitives, and were in a short time masters of the place. The whole of the French and Poitevin forces were either slain or captured; and among the prisoners were the three Lusignans, and Arthur.[380]