After the truce had been established between Richard and Saladin, Peter was assigned an important mission with other household knights, including William des Roches and Gerard de Fournival.
According to the chronicle of the crusade attributed to Geoffrey of Vinsauf, Peter had fallen asleep at one of the villages where he was to meet a Saracen embassy.
The crusaders charged ahead without receiving their safe conduct and, when Peter and his company awoke, they realized that they were already behind the Christian host.
Upon Richard's death, King John elevated Peter to his lordship over the Channel Islands in charters dated 14 January and 21 June 1200.
[1] John required Peter to provide him with 3 knights from its income (per servicium feodi trium militum) and reserved the right to exchange the islands for any other title at his pleasure.
Philip II had already begun the French conquest of Normandy in 1202, having declared John's duchy and other Continental possessions forfeit for the murder of his nephew Arthur.
Peter then took ship to England, where he was well received by King John for his service and for having maintained English control or claim over the Channel Islands.