that was the de facto government of the city. The signatories agreed to aid one another in the case of any aggression by a third party. In September 1216, with Sancho's support and probably with a following of Catalan and Aragonese knights, Raymond of Toulouse invaded France to reclaim the county of Toulouse. Simon de Montfort was killed in 1218 at the ensuing siege of Toulouse. On 26 October 1216 at Barcelona, Sancho and Nuño signed a peace treaty with Guillem Ramon de Montcada, the viscount of Béarn, his son Guillem and Guillem de Cervera. This treaty was a response to Petronilla of Bigorre's marriage to Guy de Montfort, which the viscount of Béarn considered a threatening move. The newfound allies invaded Bigorre and as a result Simon de Montfort lifted his siege of Lourdes, temporarily removing the threat the crusade posed to western flank of the Aragonese sphere. Sancho's policy of intervention in Occitania was opposed by a faction of Aragonese nobles led by his nephew, Ferdinand, abbot of Montearagón, and by those who wished to make peace with the Papacy. Ferdinand even encouraged local rebellions in Huesca, Jaca and Zaragoza. In two bulls dated 28 and 29 December 1217, Pope Honorius III threatened to excommunicate James and Sancho, respectively, and to authorise a crusade against their realm if they did not abandon Raymond VI's cause. Under pressure from several sides and apparently unwilling to abandon the Toulousain alliance, Sancho stepped down as regent. On 8 September 1218, Sancho signed an agreement with James which formally terminated the regency. He agreed to keep peace with the king and in exchange the king granted him lands and revenues: 15,000 solidi from five castles in Aragon and 10,000 solidi from Barcelona and Vilafranca. James also promised not to attack his lands or to permit anyone else from doing so for a period of seven years. This last clause secured James's neutrality in the event that Sancho continued to fight the Crusaders. The historian Ferran Soldevila considers Sancho's promise to keep the peace an indication that his resignation was not wholly voluntary. Shortly after his resignation, in the same month of September 1218, Sancho was present at the assembly in Lleida, where he was named as one of the king's advisers when James confirmed the privileges of Montpellier, which he had inherited from his mother. This same assembly appointed Guillem IV de