High Quality Content by WIKIPEDIA articles! The papal election from November 1268 to September 1, 1271, following the death of Pope Clement IV, was the longest papal election in the history of the Catholic Church. This was due primarily to political infighting between the cardinals. The election of Tebaldo Visconti as Pope Gregory X was the first example of a papal election by "Compromise." The election was effected by a Committee of six cardinals agreed to by the other remaining ten. The election occurred more than a year after the magistrates of Viterbo locked the cardinals in, reduced their rations to bread and water, and legendarily removed the roof of the Palazzo dei Papi di Viterbo.