The longest papal election took almost three years.
A papal conclave typically names the pope’s successor within just a few days after it begins. Pope Francis’ successor, for example, was chosen on the second day of the conclave. If the College of the Cardinals wanted to set a record, however, they’d have to deliberate for three years. The longest papal election lasted from 1268 to 1271 — more than two centuries before the Sistine Chapel was built — in Viterbo, Italy, following the death of Clement IV. By the time the next pope, Gregory X, was chosen after two years and nine months, the fine people of Viterbo had grown so angry with their guests, they had torn the roof off the building where the cardinals were staying.
Among the more important acts of Gregory X’s tenure was establishing a precursor to the papal conclave as we now know it, in large part to ensure that no such delay took place again. He was a little too successful. Because the rules he instituted were so strict — such as sequestering the cardinals for the duration of the conclave — it took only a day for the cardinals to name Gregory X’s successor following his death in January 1276. The new rules were suspended as a result, which naturally led to the opposite problem: a conclave that lasted from April 1292 to July 1294. Old habits die hard, but at least recent conclaves have gone comparatively smoothly now that the rules have landed in a sweet spot: It hasn’t taken more than five days to elect a new pope since 1903.
