The papal election that followed the death of Pope Clement IV lasted from 1 December 1268 to 1 September 1271 and was the longest in the history of the Catholic Church.McWhirter, Norris. 1983. Guinness Book of World Records. Bantam Books. p. 464. 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",Trollope, Thomas Adolphus. 1876. The Papal Conclaves, as They Were and as They are. Chapman and Hall. p. 54. that is, by the appointment of a committee of six cardinals agreed to by the other ten. (This method was attempted once before, in the 1227 papal election, but the choice of the committee refused the honor and the full group of cardinals proceeded to elect the pope.) 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 Palace of the Popes in Viterbo where the election took place.Bower, Archibald. 1766. The History of the Popes: From the Foundation of the See of Rome to the Present Time. p. 283-284.

As a result of the length of the election, during which three of the twenty cardinal-electors died and one resigned, Gregory X promulgated the papal bull Ubi periculum on 7 July 1274, during the Second Council of Lyon, establishing the papal conclave, whose rules were based on the tactics employed against the cardinals in Viterbo. The first election held under those rules is sometimes viewed as the first conclave.Levillain, Philippe, The Papacy: An Encyclopedia. Routledge. . p. 392.

Cardinal electors The dynamic of the conclave was divided between the French Angevin cardinals, mostly created by Pope Urban IV, who were amenable to an invasion of Italy by Charles of Anjou, and the non-French (mostly Italian) cardinals whose numbers were just sufficient to prevent a French pope from being elected.Miranda, Salvator. 1998. "Papal elections and conclaves of the 13th Century (1216-1294)." Clement IV's crowning of Charles of Anjou as King of Naples and Sicily, previously a papal fief,Baumgartner, Frederic J. 2003. Behind Locked Doors: A History of the Papal Elections. Palgrave Macmillan. . p. 41. 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.Trollope, 1876, p. 59. Conradin, the last ruler of the House of Hohenstaufen, had been beheaded in Naples just a month before the death of Clement IV.Trollope, 1876, p. 60.

At the death of Clement IV there were twenty cardinals in the Sacred College.R. Sternfeld, Der Kardinal Johann Gaetan Orsini (Papst Nikolaus III) 1244-1277 (Berlin 1905), p. 156; John Paul Adams Sede Vacante 1268-71; K. Eubel, Hierarchia Catholica Medii Aevi (1913) p. 8; cfr. Miranda, Salvator. 1998. "Papal elections and conclaves of the 13th Century (1216-1294)." Bernard Ayglerius, O.S.B., abbot of Monte Cassino, allegedly the only cardinal created by Clement IV, has been excluded from the list of the cardinals because there is no documentary proof of his cardinalate, see Eubel, p. 8 and John Paul Adams Sede Vacante 1268-71; Sternfed does not mention Bernard at all and at p.200 says that there was no creation of new cardinals between 1262 and 1273. One cardinal (Rodolphe of Albano) was absent throughout and died during the vacancy.R. Sternfeld, Der Kardinal Johann Gaetan Orsini (Papst Nikolaus III) 1244-1277 (Berlin 1905), p. 156; John Paul Adams Sede Vacante 1268-71 The other nineteen cardinals participated in the election in 1269, but two died and another left due to illness before the remaining 16 cardinals settled on a new pope.R. Sternfeld, Der Kardinal Johann Gaetan Orsini (Papst Nikolaus III) 1244-1277 (Berlin 1905), p. 156

Elector NationalityR. Sternfeld, Der Kardinal Johann Gaetan Orsini (Papst Nikolaus III) 1244-1277 (Berlin 1905), p. 156-171 Order and title ElevatedDates of promotions according to Konrad Eubel, Hierarchia Catholica Medii Aevi, (1913), I, p. 7-8. Elevator NotesOdo of ChâteaurouxFrenchCardinal-Bishop of Frascati28 May 1244Innocent IVDean of the Sacred College of CardinalsIstván Báncsa†HungarianCardinal-Bishop of PalestrinaDecember 1251Innocent IVDied on 9 July 1270,This is according to S. Miranda , and K. Eubel, Hierarchia Catholica Medii Aevi, 1913, vol. I, p. 7. John Paul Adams Sede Vacante 1268-71 denies Vancza's death in 1270, indicating that he still subscribed a letter dated 22 August 1270 and therefore, if he died on 9 July, it had to be in 1271. Paravicini Bagliani, Agostino. Cardinali di curia e "familiae" cardinalizie dal 1227 al 1254. 2 vols. Padova, Antenore, 1972. (Italia sacra, 18-19), I, p. 352 says that he died on 9 or 10 July 1270, and adds (p. 349 note 2) that on 1 September 1271 he is referred to as a dead person. The discrapencies between the recorded date of death and the date of the last subscription of Cardinal Vancsa given in Adams are possibly clarified by Ambrogio Piazzoni, Historia wyboru papieży, Kraków 2003, p. 194, which says that this letter was issued on 22 June 1270 (not 22 August). first Hungarian cardinalLevillain, 2002, p. 451.John of Toledo, O.Cist.EnglishCardinal-Bishop of Porto e Santa Rufina28 May 1244Innocent IVHenry of SegusioPiedmontese (from Susa)Cardinal-Bishop of Ostia and VelletriMay 1262Urban IVDeparted on 8 June 1270, later returnedJohn Paul Adams Sede Vacante 1268-71Simone Paltanieri (or Paltinieri, or Paltineri)PaduanCardinal-priest of Ss. Silvestro e Martino ai Monti17 December 1261Urban IVCommittee member; Cardinal primopreteSimon Monpitie de BrieFrenchCardinal-priest of S. Cecilia17 December 1261Urban IVFuture Pope Martin IVAnchero PantaleoneFrenchCardinal-priest of S. PrassedeMay 1262Urban IVCardinal-nephewGuillaume de BrayFrenchCardinal-priest of S. MarcoMay 1262Urban IV Guy de Bourgogne, O.Cist.Burgundian or CastilianCardinal-priest of S. Lorenzo in LucinaMay 1262Urban IVCommittee memberAnnibale Annibaldi, O.P.RomanCardinal-priest of Ss. XII ApostoliMay 1262Urban IVTreated with Philip III of Franceand Charles I of NaplesRiccardo AnnibaldiRomanCardinal-deacon of S. Angelo in Pescheria1238Date according to Agostino Paravicini Bagliani, Cardinali di curia e "familiae" cardinalizie dal1227 al 1254. 2 vols. Padova : Antenore, 1972. (Italia sacra, 18-19), I, p. 128Gregory IXCommittee memberNephew of Pope Alexander IV; ProtodeaconOttaviano UbaldiniFlorentineCardinal-deacon of S. Maria in Via Lata28 May 1244Innocent IVCommittee memberGiovanni Gaetano OrsiniRomanCardinal-deacon of S. Nicola in Carcere28 May 1244Innocent IVCommittee memberFuture Pope Nicholas IIIOttobono Fieschi dei Conti di LavagnaGenoeseCardinal-deacon of S. AdrianoDecember 1251Innocent IVFuture Pope Adrian V, Cardinal-nephewUberto CoconatiPiedmontese (from Asti)Cardinal-deacon of S. Eustachio17 December 1261Urban IVGiacomo SavelliRomanCardinal-deacon of S. Maria in Cosmedin17 December 1261Urban IVCommittee memberFuture Pope Honorius IVGoffredo da AlatriAlatriCardinal-deacon of S. Giorgio in Velabro17 December 1261Urban IVGiordano dei Conti Pironti da Terracina†TerracinaCardinal-deacon of Ss. Cosma e DamianoMay 1262Urban IVDied in October 1269, Vice-chancellorMatteo Rosso OrsiniRomanCardinal-deacon of S. Maria in PorticoMay 1262Urban IVNephew of Pope Nicholas III † denotes a cardinal elector who died during the election.

Absent cardinals Elector Nationality Order and title Elevated Elevator Notes† (Raoul Grosparmi)FrenchCardinal-Bishop of Albano17 December 1261Urban IVHe accompanied king Louis IX of France in his crusade in Tunisia and died there on 11 August 1270.The Cardinals of the Holy Roman Church: Raoul Grosparmi

Parties in the College of Cardinals + Nationality of Cardinal ElectorsCountryNumber of ElectorsRome5France†5Piedmont2England, Florence, Genoa, Hungary†, Alatri, Padua, Terracina†, Burgundy or Castilia1† one cardinal died before final scrutiny According to contemporary accounts in the Annales Piacentines the College of Cardinals was divided into adherents of Charles d'Anjou (pars Caroli) and the Imperial party (pars Imperii), but the exact reconstruction of these parties is very difficult.Sternfeld, p. 156 ff. and p. 317-321 It is almost certain that this account is inaccurate when it claims that pars Caroli had six (or seven, in another place in that account) members, including Giovanni Gaetano Orsini and Ottobono Fieschi, while pars Imperii had eleven (or ten) members, Riccardo Annibaldi, Ottaviano Ubaldini and Uberto Coconati among them.Sternfeld, p. 317. Certainly five cardinals, namely Ottobono Fieschi, Guillame de Bray, Anchero Pantaleone, Simon Monpitie de Brie and Odo of Châteauroux belonged to the Angevin faction.Sternfeld, p. 317-318. But if Giovanni Gaetano Orsini was really one of their leaders, then his relatives Matteo Orsini Rosso and Giacomo Savelli should also be added here, and since Henry of Segusio is also likely to have belonged to this faction, its true size would have amounted to nine cardinals. The imperial party, on the contrary, could not have had more than ten members, including two who had died during the sede vacante.Sternfeld, p. 318

According to Sternfeldp. 156-181, 317-321 it is possible to identify not only two, but as many as four parties in the Sacred College, of which two were pars Caroli and pars Imperii in the strict sense, while the remaining two represented the factions inside the Roman aristocracy: Angevin party (pars Caroli), that included Ottobono Fieschi, Guillame de Bray, Anchero Pantaleone, Simon Monpitie de Brie, probably Odo of Châteauroux and possibly Henry of Segusio, though the last two certainly represented moderate attitude Ghibeline party (pars Imperii), that included John of Toledo, Simone Paltinieri, Ottaviano Ubaldini, Uberto Coconati, and probably also Guy de Castella and two cardinals who had died in the election (Giordano Pironti and István Báncsa) Orsini faction - party of Cardinal Giovanni Gaetano Orsini, which included Matteo Orsini Rosso and Giacomo Savelli Annibaldi faction - party of Cardinal Riccardo Annibaldi, which included also his relatives Annibale Annibaldi and Goffredo da Alatri

Nevertheless, it seems that these four parties actually formed two blocs in the election: Annibaldi joined pars Imperii, while Orsini aligned himself with pars Caroli.Cfr. Sternfeld, p. 164, 169-170.

Procedure

The cardinals began the election by meeting and voting once a day in the Episcopal Palace in Viterbo, before returning to their respective residences; tradition dictated that the election should take place in the city where the previous pope died, if the late pontiff had died outside Rome. Not much reliable data is known 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.Sternfeld, p. 157-160, 170-171

According to later accounts, not supported by the contemporary sources, after two months, the cardinals nearly elected Philip Benizi, general of the Servite Order, who had come to Viterbo to admonish the cardinals, but fled to prevent his election. Also, the candidature of Saint Bonaventure had allegedly been proposed. Modern scholars treat these accounts with skepticism, considering them as products of invention of the hagiographers of these two saints.

Charles of Anjou was in Viterbo for the entirety of the election;The Quarterly Review. 1896. p. 511-512. Philip III of France visited the city in March 1271.