Ubi periculum
PAPAL BULL REGARDING THE ELECTION OF POPES
Ubi Periculum
Ubi periculum is a papal bull promulgated by Pope Gregory X during the Second Council of Lyon on 7 July 1274 that established the papal conclave format as the method for selecting a pope, specifically the confinement and isolation of the cardinals in conditions designed to speed them to reach a broad consensus. Its title, as is traditional for such documents, is taken from the opening words of the original Latin text, , 'Where greater danger lies'.