Pope Sylvester I in the context of "Donatism"

Eusebius of Nicomedia (/juːˈsiːbiəs/; Ancient Greek: Εὐσέβιος; died 341) was an Arian priest who baptised Constantine the Great on his deathbed in 337. A fifth-century legend evolved that Pope Sylvester I was the one to baptise Constantine, but this is dismissed by scholars as a forgery "to amend the historical memory of the Arian baptism that the emperor received at the end of his life, and instead to attribute an unequivocally orthodox baptism to him". He was a bishop of Berytus (modern-day Beirut) in Phoenicia. He was later made the bishop of Nicomedia, where the Imperial court resided. He lived finally in Constantinople from 338 up to his death.

The Schola Cantorum was the trained papal choir during the Middle Ages, specializing in the performance of plainchant for the purpose of rendering the music in church. In the fourth century, Pope Sylvester I was said to have inaugurated the first Schola Cantorum, but it was Pope Gregory I who established the school on a firm basis and endowed it. The choir ranged anywhere from twenty to thirty boys or men. Only the most skilled in singing were selected to participate in the Schola Cantorum.

Saint Sylvester's Day, also known as Silvester or the Feast of Saint Sylvester, is the day of the feast of Pope Sylvester I, a saint who served as Pope from 314 to 335. Medieval legend made him responsible for the conversion of emperor Constantine. Among the Western churches, the feast day is held on the anniversary of Saint Sylvester's death, 31 December, a date that, since the adoption of the Gregorian calendar, has coincided with New Year's Eve. For these Christian denominations, Saint Sylvester's Day liturgically marks the seventh day of Christmastide. Eastern churches celebrate Sylvester's feast on a different day from the Western churches, i.e. on 2 January. Saint Sylvester's Day celebrations are marked by church attendance at a Watchnight Mass that is often held around midnight, as well as fireworks, partying, and feasting.

Constantine the Great's (272–337) relationship with the four Bishops of Rome during his reign is an important component of the history of the Papacy, and more generally the history of the Catholic Church.

The legend surrounding Constantine I's victory in the Battle of the Milvian Bridge (312) relates his vision of the Chi Rho (☧) and the text in hoc signo vinces in the sky and his reproducing this symbol on the shields of his troops. The following year Constantine and Licinius proclaimed the toleration of Christianity with the Edict of Milan, and in 325 Constantine convened and presided over the First Council of Nicaea, the first ecumenical council. None of this, however, has particularly much to do with the popes, who did not even attend the Council; in fact, the first bishop of Rome to be contemporaneously referred to as "Pope" (πάππας, or pappas) is Damasus I (366-384). Moreover, between 324 and 330, he built Constantinople as a new capital for the empire, and—with no apologies to the Roman community of Christians—relocated key Roman families and translated many Christian relics to the new churches.