He took part in the Fifth Crusade and was against the Sultan of Egypt's conditions for raising the siege of Damietta.

A close friend of William of Chartres, it was most likely the trust the previous Grand Master had in him which meant he himself was elected so quickly in 1218.

At the same time, the Grand Master of the Knights Hospitaller was Guérin de Montaigu, who is likely to have been Pere's brother.

Catholic pressure meant the Muslim terms were refused and the carnage continued.

His military victories, aided by the Hospitaller knights, made him a renowned warrior.