Papal authority went to Urban's head, and his attempts at reform and his outbursts of temper did not sit well with the college of cardinals, who soon began to regret their decision. In an extraordinary move, several of them met in Anagni in central Italy and had a second election on 20 September. They claimed that the election of Urban was illegitimate because it was due to threats of intimidation and violence, and so they justified themselves in electing Robert of Geneva as Pope Clement VII. Unable to reside at the Vatican due to Urban's presence, Clement and the supporting cardinals returned to Avignon.
Thus was born the Western Schism, also called the Papal Schism or the Schism of 1378. The world had no choice but to take notice, and to take sides. Rome had the support of the Italian states, the Holy Roman Empire, England, and much of Eastern Europe and the Scandinavian countries. Avignon was supported by France, the kingdoms on the Iberian peninsula, Scotland, and several Mediterranean countries. Some nations shifted their allegiance over timeNaples, Bohemia, Flanders and Portugal (among others), started with Avignon and later switched as Rome seemed to be a safe, traditional choice.
Urban vs. Clement was only the start. Urban was succeeded by Boniface IX, then by Innocent VII, then by Gregory XII. Clement was replaced by Benedict XIII.
Now we come to Peter of Candia: had been made a cardinal by Innocent VII in 1405, and his greatest desire was to reconcile the schism. When Innocent was succeeded by Gregory, Gregory made a move that shocked both Avignon and Rome, and would lead to the next step: a solution put forth in Pisa.
By 1409, the Italian city-state of Pisa had had enough of the controversy. They decided that 30 years of papal confusion and chaos needed to be resolved, and the only way they could think of to do so was . . . (wait for it) to elect another pope!