Pope Gregory X
He was Archdeacon of Vermoim (Vermuy) in the Archdiocese of Braga. He tried to become bishop of Lisbon but was defeated. Instead, he became the Master of the school of Lisbon. Peter became the physician of Pope Gregory X (1271–76) early in his reign. In March 1273 he was elected Archbishop of Braga, but did not assume that post; instead, on 3 June 1273, Pope Gregory X created him Cardinal Bishop of Tusculum (Frascati).