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 couldn’t reach a consensus before September 1271.