Cardinals walk in procession to the Sistine Chapel at the Vatican, at the beginning of the conclave, April 18, 2005. (Osservatore Romano via AP, File)2025-05-04T04:08:04Z VITERBO, Italy (AP) It was the mounting rage of citizens in Viterbo, a small town north of Rome, that put an end to the longest papal election in the history of the Catholic Church, forging for the first time the word conclave.The Viterbo conclave in the 13th century was a pivotal event in papal elections, lasting almost three years exactly 1,006 days due to deep divisions among the cardinals over the name of the new pope.Viterbo is also considered the birthplace of modern conclaves, where cardinals are confined to a single place until they elect a new pontiff, and often need to negotiate before reaching a compromise on the final name. In November 1268, the cardinals -- summoned in Viterbo to elect the successor of the late Pope Clement IV -- were split mainly between two factions and couldnt reach a consensus before September 1271. Drastic measuresAs the cardinals continued to deliberate in Viterbo, frustration rose among locals due to the lack of progress, as political and internal struggles had cast a shadow over the election.Those divisions stemmed from the cardinals allegiance to competing parties, mainly supporters of the papacy and the Holy Roman Empire. That was further complicated by personal and family ties, making any agreement on the popes election extremely difficult. The electing marathon led citizens ,who at the time had to pay for the cardinals room and board expenses, to resort to drastic measures. The cardinals were first locked in Viterbos papal palace with a key, giving birth to the term conclave, which comes from the Latin words cum (with) and clavem (key). The cardinals left us a very important testimony, a parchment, dated June 8, 1270, where they said to be locked inside a palazzo discoperto, a palace with no roof, said Elena Cangiano, an archaeologist at Viterbos medieval Palazzo dei Papi (Palace of the Popes). Cangiano noted that, according to Viterbo oral tradition, the cardinals ended up camping inside the unroofed palace.Thats reportedly testified by some holes found on the halls floor, which could be those left by the tents poles, she explained. Then Viterbese also restricted the cardinals meals to bread and water to make them hurry up. As that didnt work either, they started tearing off part of the roof of the large room that hosted the college of cardinals, exposing them to the elements.Those extreme conditions only lasted three weeks, following which the cardinals were allowed access to the other rooms of the palace, but not to leave the building. It would take another 15 months before Gregory X was chosen as the new pope. That was the longest papal election ever: To avoid the same situation ever occurring again, Gregory X promulgated a new apostolic constitution called Ubi Periculum that imposed strict regulations on the election and allowed to isolate the cardinals. Gregorys election was also seen as a compromise, with his name chosen to unite the divided college of cardinals and bring an end to the exhausting process. Modern conclaveThats why the Viterbo conclave is seen by historians as setting the stage for future papal elections. The rules and practices established at the time laid the foundation for many of the procedures used currently in papal conclaves.Among the new rules, Gregorio X decreed that cardinals were restricted to one meal per day, and later, to bread, water and wine, to further encourage a quick decision. The newly elected Adrian V, however, suspended those rules a few years later. Fabrizio Cardoni, 61, born and raised in Viterbo, considers the citys primacy a matter of pride.This is the history of our city, he said. So, we care a lot about our medieval neighborhood, we care about the pope palace that is truly wonderful and, lets say, almost unique.Cristina Giusio, a tourist visiting from northern Italy, was struck by the history of the Viterbo conclave after a tour of the papal palace. It was something quite amazing. ... I did not know that first conclave started here, so it was a real surprise, she said. Vatican history experts stress that modern conclaves still owe to Viterbo some of their key characteristics, including shorter durations. Viterbos legacy could again play a role again in the conclave that starts on Wednesday in Romes Sistine Chapel to choose Pope Francis successor.Lets say that the timing is now almost certainly respected, also thanks to all that happened in Viterbo, said Cangiano. In recent times, usually, it doesnt take that long to elect the pope.___Associated Press video journalist Isaia Montelione contributed to this report.