Western Schism
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. The papacy had resided in Avignon since 1309, but Pope Gregory XI returned to Rome in 1377. The Catholic Church split in 1378 after Gregory XI's death and Urban VI's election. 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 Antipope John XXIII called the Council of Constance (1414–1418). The Council arranged the renunciation of both Roman pope Gregory XII and Pisan antipope John XXIII. The Avignon antipope Benedict XIII was excommunicated, while Pope Martin V was elected and reigned from Rome. The affair is