After Gregory XI died, the Romans rioted to ensure the election of a Roman for pope. The cardinals, fearing the crowds, elected a Neapolitan when no viable Roman candidates presented themselves. Pope Urban VI, born Bartolomeo Prignano, the Archbishop of Bari, was elected in 1378. Urban had been a respected administrator in the papal chancery at Avignon, but as pope he proved suspicious, overbearing, and prone to violent outbursts of temper. The cardinals who had elected him soon regretted their decision: the majority removed themselves from Rome to Anagni, where they elected Robert of Geneva as a rival pope on September 20 of the same year. Robert took the name Pope Clement VII and reestablished a papal court in Avignon. The second election threw the Church into turmoil. There had been antipopes--rival claimants to the papacy--before, but most of them had been appointed by various rival factions; in this case, a single group of leaders of the Church had created both the pope and the antipope.
The conflicts quickly escalated from a church problem to a diplomatic crisis that divided Europe. Secular leaders had to choose which claimant they would recognize:
|France, Aragon, Castile and León, Cyprus, Burgundy, Savoy, Naples, and Scotland recognized the Avignon claimant;||Denmark, England, Flanders, the Holy Roman Empire, Hungary, northern Italy, Ireland, Norway, Poland, and Sweden recognized the Roman claimant.|
Sustained by such national and factional rivalries throughout Catholic Christendom, the schism continued after the deaths of both initial claimants; Boniface IX, crowned at Rome in 1389, and Benedict XIII, who reigned in Avignon from 1394, maintained their rival courts. When Boniface died in 1404, the eight cardinals of the Roman conclave offered to refrain from electing a new pope if Benedict would resign; but when his legates refused on his behalf, the Roman party then proceeded to elect Pope Innocent VII.
Efforts were made to end the Schism through force or diplomacy. The French crown even tried to coerce Benedict XIII, whom it nominally supported, into resigning. None of these remedies worked. The suggestion that a church council should resolve the Schism, first made in 1378, was not adopted at first because canon law required that a pope call a council. Eventually theologians like Pierre d'Ailly and Jean Gerson, as well as canon lawyers like Francesco Zabarella, adopted arguments that equity permitted the Church to act for its own welfare in defiance of the letter of the law.
Eventually the cardinals of both factions secured an agreement that Benedict and Gregory XII would meet at Savona. They balked at the last moment, and both colleges of cardinals abandoned their popes. A church council was held at Pisa in 1409 under the auspices of the cardinals to try solving the dispute, but it added to the problem by electing another antipope, Alexander V. He reigned briefly from June 26, 1409, to his death in 1410, when he was succeeded by John XXIII, who won some but not universal support.
The line of Roman popes is now recognized as the legitimate line, but this was not true before the 19th century. Efforts to tidy up Church history led to the claim that Gregory XII had legitimized the Council of Constance. Consistent with this outcome, Pope Pius II decreed that no appeal could be made from pope to council; this left no way to undo a papal election by anyone but the elected pope. No such crisis has arisen since the 15th century, and so there has been no need to revisit this decision. The alternate papal claimants have become known in history as antipopes. Those of Avignon were dismissed by Rome early on, but the Pisan popes were included in the Annuario Pontificio well into the 20th century. Thus the Borgia pope Alexander VI took his regnal name in sequence after the Pisan Alexander V.