"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. Upon becoming pope, Marcellus persecuted Christian backsliders so viciously that the Roman Emperor Maxentius banned him from the city to avoid public disorder. Marcellus was later made a saint. [Curran, 16-18, McBrien, 55]"