Sylvester I, Saint, pope (314–35), a Roman; successor of St. Miltiades (St. Melchiades). He was pope under the reign of Emperor Constantine I, who built for him the Lateran and other churches. St. Sylvester sent legates to the First Council of Nicaea and took strong interest in the controversy over Arianism. The spurious Donation of Constantine (see Constantine, Donation of) was supposedly given to St. Sylvester. The name is also spelled Silvester. He was succeeded by St. Marcus. Feast: Dec. 31.