The Western Schism, also known as the Papal Schism, the Great Occidental Schism, or the Schism of 1378 (Magnum schisma occidentale, Ecclesiae occidentalis schisma), 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. These rival claims to the papal throne damaged the prestige of the office.
The papacy had resided in Avignon since 1309, but Pope Gregory XI returned to Rome in 1377. However, the Catholic Church split in 1378 when, after Gregory XI died and Urban VI had been elected in Rome, a group of French cardinals declared his election invalid and elected Clement VII as pope. After several attempts at reconciliation, the Council of Pisa (1409) declared that both rivals were illegitimate and elected a third purported pope. The schism was finally resolved when the Pisan claimant John XXIII called the Council of Constance (1414–1418). The Council arranged the renunciation of both the Roman pope Gregory XII (who peacefully resigned) and the Pisan antipope John XXIII, excommunicated the Avignon antipope Benedict XIII, and elected Martin V as the new pope reigning from Rome.
The affair is sometimes referred to as the Great Schism, although this term is usually used for the East–West Schism of 1054 between the Churches remaining in communion with the See of Rome and the Eastern Orthodox Churches.
Since 1309, by decision of Pope Clement V, the papacy had resided in Avignon, a papal enclave surrounded by France. The Avignon Papacy had developed a reputation for corruption that estranged major parts of Western Christendom. This reputation can be attributed to perceptions of predominant French influence, and to the papal curia's efforts to extend its powers of patronage and increase its revenues.