""Manichaeans were expelled from Rome and threatened with exile from all Roman territory." [Engh, 94]"
"Pope Eusebius, like his predecessor Marcellus, was involved in the dispute over the treatment of backsliders. Also like Marcellus, the dispute was so disruptive to civil order that he was deported by Emperor Maxentius. He was also made a saint. [McBrien, 55-56]"
"Pope Marcellus I is not mentioned in Eusebius' History of the Church. Annuario Pontifico, the Vatican's official directory of the popes gives his dates in office as 308-309. The New American Bible gives them as 304-309.