Pope Martin V, born Otto 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".
Portrait of Martin V after Pisanello
Pope Martin's election as pope. Chronicle of Ulrich of Richenthal.
The Western Schism, also known as the Papal Schism, the Great Occidental Schism, or the Schism of 1378, was a split within the Catholic Church lasting from 1378 to 1417 in which bishops residing in Rome and Avignon both claimed to be the true pope, and were joined by a third line of Pisan claimants in 1409. The schism was driven by personalities and political allegiances, with the Avignon Papacy being closely associated with the French monarchy.
A 14th-century miniature symbolizing the schism
Habemus Papam at the Council of Constance
Plaque commemorating the popes buried in St. Peter's. Alexanders VI, VII, and VIII are numbered as though the Pisan pope Alexander V were legitimate, but John XXIII (d. 1963) has reused the ordinal of the Pisan pope John XXIII.