Clement VII is elected on September 20, 1378 as a rival pope in Avignon by a majority of the cardinals seceding from Rome. The events leading to the Western Schism began after Pope Gregory XI's death in March 1378, with the election of Urban VI on April 8, 1378,
The creation of two competing papal claimants divided the Catholic Church. The schism was finally resolved 40 years later at the Council of Constance in 1417-1418 , which led to the election of a single pope, Martin V.