Answer
The 1261 Conclave was the conclave held in Viterbo, Italy, from October 21 to October 29, 1261, to elect a successor to Pope Alexander IV, who had died on October 25. The conclave was prolonged by the refusal of the cardinals to elect a candidate who would be unacceptable to King Louis IX of France, who was then besieging the city of Viterbo.