Pope Sylvester I serves as pope from 31 January 314 to 31 December 335, succeeding Pope Miltiades.

He fills the See of Rome at an important era in the history of the Catholic Church, yet very little is known of him.

The accounts of the papacy of Pope Sylvester I preserved in the Liber Pontificalis (7th or 8th century) are little else than a record of the gifts said to have been conferred on the Church by Constantine I, but it does say that he was the son of a Roman named Rufinus.

During his pontificate are built the great churches founded at Rome by Constantine, e.g.

the Basilica of St. John Lateran, Santa Croce in Gerusalemme, St. Peter's Basilica, and several cemeterial churches over the graves of martyrs.

Sylvester does not himself attend the First Council of Nicaea in 325, but he is represented by two legates, Vitus and Vincentius, and he approves the council's decision.

Part of the Symmachean forgeries, the Vita beati Sylvestri (c. 501–508), which has been preserved in Greek and Syriac, and in Latin in the Constitutum Sylvestri, is an apocryphal account of an alleged Roman council, introducing legends of Sylvester's close relationship with the first Christian emperor.

They also appear in the Donation of Constantine.