Pope Mark (Latin: Marcus) was the bishop of Rome from 18 January to his death on 7 October 336. Little is known of Mark's early life. According to the Liber Pontificalis, he was a Roman, and his father's name was Priscus. Mark succeeded Sylvester I as pope on 18 January 336.
Some evidence suggests that the early lists of bishops and martyrs known as the Depositio episcoporum and Depositio martyrum were begun during his pontificate. According to the Liber Pontificalis, Pope Mark issued a constitution investing the bishop of Ostia with a pallium and confirming his power to consecrate newly elected popes.