Pope Martin I, also known as Martin the Confessor, was the bishop of Rome from 21 July 649 to his death 16 September 655. He had served as Pope Theodore I's ambassador to Constantinople, and was elected to succeed him as Pope. He was the only pope when Constantinople controlled the papacy whose election had not awaited imperial mandate. For his strong opposition to Monothelitism, Pope Martin I was arrested by Emperor Constans II, carried off to Constantinople, and ultimately banished to Cherson. He is considered a saint by both the Catholic Church and the Eastern Orthodox Church. He is the last pope recognised as a martyr.

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.