The cause of the so-called Western Schism was the temporary residence of the popes at Avignon, France, which began in 1309 under Pope Clement V. This exile from the Eternal City met with opposition, especially in Italy where the people clamoured for the return of the sovereign pontiff. Finally in 1376 Pope Gregory XI re-established his see in Rome, and on his death in 1378, the future residence of the vicars of Christ was the main issue in the subsequent conclave. The cardinals meeting in the Holy City duly elected Urban VI, an Italian. General dissatisfaction, especially on the part of the French members of the Sacred College, and disagreement concerning the validity or the choice led to a second conclave at Fondi (20 September) and the election of another pope, a Frenchman, as Clement VII, who immediately took up his residence in Avignon. As both claimed to be legitimate successors, the Western Church quickly divided into two camps, each supporting one or the other.
There was really no schism, for the majority of the people desired unity under one head and intended no revolt against papal authority. Everywhere the faithful faced the anxious problem: where is the true pope? Even saints and theologians were divided on the question. Unfortunately, led by politics and human desires, the papal claimants launched excommunications against each other, and deposed secular rulers who in turn forbade their subjects to submit to them. This misunderstanding lasted forty years (1378 to 1417).
An attempt to mend the breach in the Council of Pisa in 1409 produced a third claimant, and the schism was not terminated until the Council of Constance (1414 to 1418), which deposed the Pisan, John XXIII, received the abdication of the Roman, Gregory XII, dismissed the Avignon Benedict XIII, and finally elected an undisputed pope, Martin V, on 11 November 1411.
The list of Roman, Avignon, and Pisan popes is