Pope Sergius I was the bishop of Rome from 15 December 687 to his death, and is revered as a saint by the Roman Catholic Church. He was elected at a time when two rivals, Paschal and Theodore, were locked in a dispute about which of them should become pope. His papacy was dominated by his response to the Quinisext Council, the canons of which he steadfastly refused to accept. Thereupon Emperor Justinian II ordered Sergius' arrest, but the Roman people and the Italian militia of the exarch of Ravenna refused to allow the exarch to bring Sergius to Constantinople.

The selection of the Pope, the Bishop of Rome and Supreme Pontiff of the Catholic Church, prior to the promulgation of In Nomine Domini in AD 1059 varied throughout history. Popes were often putatively appointed by their predecessors or by political rulers. While some kind of election often characterized the procedure, an election that included meaningful participation of the laity was rare, especially as the Popes' claims to temporal power solidified into the Papal States. The practice of papal appointment during this period would later result in the putative jus exclusivae, i.e., the claimed but invalid right to veto the selection that Catholic monarchs exercised into the twentieth century.