Alexander V

c.1339-1410. Pope from 1409. Peter of Crete, Greek by birth, became a Franciscan and studied at Oxford and Paris where he became master of theology (1381) and lectured on the Sentences of Peter Lombard. His Commentary, which has survived, shows Nominalistic leanings and suggests that he played a role of some importance in the development of medieval thought. He became bishop of Piacenza (1386), Vicenza (1387), Novara (1389), and archbishop of Milan (1402). In an effort to end the Great Schism he was chosen by the Council of Pisa (1409) in place of two rival popes. He died less than a year later, and there is some doubt as to the validity of his reign. The council had no authority in strict canon law, as it was summoned not by papal order but by certain cardinals who had deserted the two rival popes.