Pope Martin V (; ; January/February 1369 – 20 February 1431), born Otto (or Oddone) Colonna, was the head of the Catholic Church and ruler of the Papal States from 11 November 1417 to his death in February 1431. His election effectively ended the Western Schism of 1378–1417. He is the last pope to date to take on the pontifical name "Martin". Biography Oddone Colonna was born at Genazzano, the son of Agapito Colonna and Caterina Conti, between 26 January and 20 February, 1369. He belonged to one of the oldest and most distinguished families of Rome. His brother Giordano became Prince of Salerno and Duke of Venosa, while his sister Paola was Lady of Piombino between 1441 and 1445. Oddone studied law at the University of Pavia. He became apostolic protonotary under Pope Urban VI (1378–1389), and was created Cardinal-Deacon of San Giorgio in Velabro by Pope Innocent VII in 1405. In 1409 he took part in the Council of Pisa, and was one of the supporters of Antipope Alexander V. Later he confirmed his allegiance to Alexander's successor, John XXIII, by whom his family obtained several privileges, while Oddone obtained for himself the vicariate of Todi, Orvieto, Perugia and Umbria. He was excommunicated for this in 1411 by Pope Gregory XII. Oddone was with John XXIII's entourage at the Council of Constance and followed him in his escape at Schaffhausen on 21 March 1415. Later he returned to Constance and took part in the process leading to the deposition of John XXIII. Papacy Election After deposing Antipope John XXIII in 1415, the Council of Constance was long divided by the conflicting claims of Pope Gregory XII (1406–15) and Antipope Benedict XIII (1394–1423). Martin was elected pope, at the age of 48, at the Council of Constance on St. Martin's Day, 11 November 1417. Participants in the conclave included 23 cardinals and 30 delegates of the council. He was ordained a priest on 13 November, 1417, and consecrated bishop the next day. Martin left Constance at the close of the council (May 1418), but travelled slowly through Italy and lingered at Florence. His authority in Rome was represented by his brother Giordano, who had fought under Muzio Attendolo against the condottiero Braccio da Montone. The Pope at the time ruled only Rome (when not rebellious) and its environs: Braccio held Umbria, Bologna as an independent commune, while much of