Pope Innocent V, born Pierre de Tarentaise, was head of the Catholic Church and ruler of the Papal States from 21 January to 22 June 1276. A member of the Order of Preachers, he acquired a reputation as an effective preacher. He held one of the two "Dominican Chairs" at the University of Paris, and was instrumental in helping with drawing up the "program of studies" for the Order. In 1269, Peter of Tarentaise was Provincial of the French Province of Dominicans. He was a close collaborator of Pope Gregory X, who named him Bishop of Ostia and raised him to cardinal in 1273.

Pope Gregory X, born Teobaldo Visconti, was head of the Catholic Church and ruler of the Papal States from 1 September 1271 to his death and was a member of the Secular Franciscan Order. He was elected at the conclusion of a papal election that ran from 1268 to 1271, the longest papal election in the history of the Catholic Church.