The January 1276 papal conclave, was the 1st papal conclave. held under the rules of constitution Ubi periculum issued by Pope Gregory X in 1274, which established papal conclaves. According to Ubi periculum Cardinals were to be secluded in a closed area; they were not even accorded separate rooms. No cardinal was allowed to be attended by more than one servant unless ill. Food was to be supplied through a window; after three days of the meeting, the cardinals were to receive only one dish a day; after five days, they were to receive just bread and water. During the conclave, no cardinal was to receive any ecclesiastical revenue. These provisions were regularly disregarded, at the discretion of the cardinals, particularly the requirement of being incommunicado.

The 1268–71 papal election, 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 Teobaldo Visconti as Pope Gregory X was the first example of a papal election by "compromise", that is, by the appointment of 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 removed the roof of the Palazzo dei Papi di Viterbo where the election took place.