"dismay soon gave way to panic as the sixteen cardinals assembled on April 7 1378. Some of them were assaulted in the street and warned by the bullies to elect (Urban vi) an Italian... The cardinals quickly elected an Italian, the archbishop of Bari, Bartholomew Prignano, who was not even of their number. In the meantime, a mob in ugly mood had seized the papal wine cellars and invaded the Vatican; while waiting for Prignano to arrive, the cardinals dressed up one of their colleagues and presented him in papal robes to pacify the crowd.
Whether the cardinals were really overpowered by fear and hence unfree when they elected Prignano - as they later charged - will, it seems, remain forever one of the tantalizing but insoluble questions of RC history...
The schism began when the cardinals - whose original misgivings were greatly exacerbated by Urban's behavior - decided they had had enough. Abandoning Rome, they took refuge at Fondi, and then elaborated an encyclical in which they declared Prignano's election invalid and denounced him has antichrist, demon, apostate, and tyrant...on September 20 1378 they unanimously elected a new Pope, Rober of Geneva, who took the name Clement VII.
..both Popes received support from civil governments - splitting western Christendom into two camps. The holy Roman emperor, England, the Netherlands, Castille, Hungary, Poland and Portugal stood behind Urban, while France rallied to Clement VII, who returned to Avignon in 1379 and was soon joined by Scottland, Luxembourg and Austria...(Italy itself was too confused for either side to count on)...
Urban proclaimed a crusade against clement and hired the sanguinary Charles of Durazzo to oust the renegade queen Joan from Naples. The English invaded France in order to break it's allegiance with Clement
.
Both Popes found military operations to be expensive, and the papal tax collectors where forced to use ever harsher methods to squeeze every penny out of the constituents...Urban turned more violent and savage. Suspecting his own cardinals of plotting against him, he put them to torture, and five of them died shortly thereafter, probably thrown overboard from the Pope's warship … Urban returned to Rome where he died in 1389. His fourteen cardinals immediately elected a successor..Boniface ix...
This rupture of the church's unity was a terrible trial for believing Catholics."