to secure the cooperation of all his vassals in his plans for the invasion, Philip denounced John as an enemy of the Church, thereby justifying his attack as motivated solely by religious scruples. He summoned an assembly of French barons at Soissons, which was well attended. The only exception was Count Ferdinand of Flanders, who refused out of anger over the loss of the towns of Aire and Saint-Omer that had been captured by Philip's son Louis the Lion. He would not participate in any campaign until he was restored to his ancient lands. Philip was eager to prove his loyalty to Rome and thus secure papal support for his planned invasion, announced at Soissons a reconciliation with his estranged wife Ingeborg of Denmark, which the popes had been promoting. The barons fully supported his plan, and they all gathered their forces and prepared to join with Philip at the agreed rendezvous. Through all of this, Philip remained in constant communication with Pandulf Verraccio, the papal legate, who was encouraging Philip to pursue his objective. Verraccio however was also holding secret discussions with King John. Advising the English king of his precarious predicament, he persuaded John to abandon his opposition to papal investiture and agreed to accept the papal legate's decision in any ecclesiastical disputes as final. In return, the pope agreed to accept the Kingdom of England and the Lordship of Ireland as papal fiefs, which John would rule as the pope's vassal, and for which John would do homage to the pope. No sooner had the treaty between John and the pope been ratified in May 1213 than Verraccio announced to Philip that he would have to abandon his expedition against John, since to attack a faithful vassal of the Holy See would be a mortal sin. Philip argued in vain that his plans had been drawn up with the consent of Rome, that his expedition was in support of papal authority that he only undertook on the understanding that he would gain a plenary indulgence; he had spent a fortune preparing for the expedition. The papal legate remained unmoved, but Verraccio did suggest an alternative. The Count of Flanders had denied Philip's right to declare war on England while King John was still excommunicated, and that his disobedience needed to be punished. Philip eagerly accepted the advice, and quickly marched at the head of his troops into