Following a disputed papal election marred by mob pressure in Rome, French cardinals declared Urban VI's election invalid and chose Clement VII instead, establishing a rival papal court in Avignon. The resulting Western Schism divided Europe's loyalties along political lines and was resolved only by the Council of Constance decades later.
The roots of the schism lay in chaos: when Pope Gregory XI died in 1378, Roman crowds, fearful that French cardinals would again choose a Frenchman and return the papacy to Avignon (as had been the case for nearly seventy years), surrounded the conclave and demanded a Roman or at least Italian pope. Under this pressure, cardinals elected Bartolomeo Prignano as Urban VI.
Urban proved erratic and authoritarian almost immediately, alienating the same cardinals who had elected him. Retreating to Anagni, a group of predominantly French cardinals declared the election invalid, claiming they had acted under duress, and in September 1378 elected Robert of Geneva as Clement VII instead. Clement soon established his court back in Avignon, effectively creating two competing popes, two curias, and two claims to Christ's authority on Earth.
Europe split along political lines—France, Scotland, and Aragon backed Avignon, while England, the Holy Roman Empire, and much of Italy backed Rome—less from theological conviction than geopolitical rivalry. The schism dragged on for nearly forty years, at one point producing three simultaneous claimants to the papacy, and was only resolved by the Council of Constance (1414–1418), which forced resignations and elected Martin V as the sole, universally recognized pope.
Key people: Robert of Geneva, Urban VI