[6] Clement IV's crowning of Charles of Anjou as King of Naples and Sicily, previously a papal fief,[7] had cemented the influence of the French monarchy in the Italian peninsula and created an intense division within the College of Cardinals between those who opposed and supported French influence, and by extension, ultramontanism.

There is little reliable data about the candidates proposed during almost three years of deliberations; certainly cardinals Odo of Châteauroux, John of Toledo, Giovanni Gaetano Orsini, Ottaviano Ubaldini, Riccardo Annibadi and Ottobono Fieschi were counted among the papabili.

[7] In late 1269, after several months of deadlock during which the cardinals had met only intermittently,[30] Ranieri Gatti,[31] the Prefect of Viterbo, and Albertus de Montebono, the Podesta, ordered (some sources say, at the urging of Saint Bonaventure[32]) the cardinals sequestered in the Palazzo dei Papi di Viterbo until a new pope was elected.

[5] On 8 June 1270, the cardinals addressed a Diploma to the two magistrates asking that Henry of Segusio, Cardinal-Bishop of Ostia, be dismissed from the "Palatio discooperto" ("the uncovered Palace") owing to his ill health and his having already renounced his right to vote.

[5] Other sources say it was Charles of Anjou who orchestrated the reduction of the diet of the cardinals to bread and water and the removal of the roof of the Papal Palace.

[33] Under pressure from Philip III of France and other rulers, on 1 September 1271, the cardinals agreed to cede their authority to a committee of six.

[34] The committee chose an Italian from Piacenza, Teobaldo Visconti, a non-cardinal, who was then in Acre with the retinue of Edward (the eldest-son of Henry III of England) as papal legate to the Ninth Crusade.

[33] Popular accounts of the conclave, as early as those of French historian Georges Goyau, neglect to mention the political intrigue of Charles I of Naples or his nephew, Philip III of France, as the masterminds of the hardships employed by the "citizens of Viterbo.

"[33] Designed both to accelerate future elections and reduce outside interference, the rules of Ubi periculum provide for the cardinal electors to be secluded for the entirety of the conclave, including having their meals passed through a small opening, and for their rations to be reduced to a single meal at the end of three days, or bread and water (with a little wine) after eight days.