Pope Marcellus I () (6 January 255 – 16 January 309) was the bishop of Rome from May or June 308 to his death on 16 January 309. He succeeded Marcellinus after a considerable interval. Under Maxentius, he was banished from Rome in 309, on account of the tumult caused by the severity of the penances he had imposed on Christians who had lapsed under the recent persecution. He died the same year, being succeeded by Eusebius. His relics are under the altar of San Marcello al Corso in Rome. Since 1969 his feast day, traditionally kept on 16 January by the Catholic Church, is left to local calendars and is no longer inscribed in the General Roman Calendar.
Election
For some time after the death of Marcellinus in 304, the Diocletian persecution continued with unabated severity. After the abdication of Diocletian in 305, and the accession in Rome of Maxentius to the throne of the Caesars in October of the following year, the Christians of the capital again enjoyed comparative peace. Nevertheless, nearly two years passed before a new bishop of Rome was elected. Then in 308, according to the Catalogus Liberianus, Marcellus first entered on his office: "He was bishop in the time of Maxentius, from the 4th consulship of Maxentius when Maximus was his colleague, until after the consulship." At Rome, Marcellus found the church in the greatest confusion. The meeting-places and some of the burial-places of the faithful had been confiscated, and the ordinary life and activity of the church was interrupted. Added to this were the dissensions within the church itself, caused by the large number of weaker members who had fallen away during the long period of active persecution and later, under the leadership of an apostate, violently demanded that they should be readmitted to communion without doing penance. At the beginning of the 7th century, there were probably twenty-five "title" churches in Rome; even granting that, perhaps, the compiler of the Liber Pontificalis referred this number to the time of Marcellus, there is still a clear historical tradition in support of his declaration that the ecclesiastical administration in Rome was reorganized by this pope after the great persecution.