Pope Celestine V, born Pietro Angelerio, also known as Pietro da Morrone, Peter of Morrone, and Peter Celestine, was head of the Catholic Church and ruler of the Papal States for five months from 5 July to 13 December 1294, when he resigned. He was also a monk and hermit who founded the order of the Celestines as a branch of the Benedictine order.

The 1292–94 papal election, was the last papal election which did not take the form of a papal conclave. After the death of Pope Nicholas IV on 4 April 1292, the eleven surviving cardinals deliberated for more than two years before electing the third of six non-cardinals to be elected pope during the Late Middle Ages: Pietro da Morrone, who took the name Pope Celestine V.