Saint Sylvester I was Bishop of Rome from January 31, 314, until his repose on December 31, 335 — one of the longest-serving bishops of Rome in the early Church, and one venerated by the Orthodox among the pre-schism saints of the West. He succeeded Pope Miltiades shortly after the legalization of Christianity under the emperor Constantine.
According to the Liber Pontificalis he was a Roman, the son of a man named Rufinus; reliable detail of his early life is scarce, though he appears to have been formed within the Christian community of Rome and ordained before his elevation. He took up the leadership of the Roman Church at a moment of profound change: the persecution under Diocletian had recently ended, and the Church was emerging into public life, able for the first time to build openly and to organize without fear of suppression.
Several of Rome's most important churches were founded during his episcopate — the original basilicas associated with Saint John Lateran, Saint Peter, and the Holy Cross in Jerusalem — projects largely financed by Constantine but established under Sylvester's oversight of the Roman Church. When the First Ecumenical Council met at Nicaea in 325 to confront the Arian controversy, Sylvester did not attend in person, likely on account of age, but sent legates who took part on behalf of Rome; the council affirmed the divinity of Christ and gave the Church the Nicene Creed.
Later medieval legend claimed that Sylvester personally baptized Constantine and healed him of leprosy, but the earlier sources indicate that Constantine was baptized only near the end of his life, by Eusebius of Nicomedia. Sylvester reposed in peace in 335 after more than two decades as bishop; unlike many of his predecessors he was not martyred, a sign of the new peace that followed Christianity's legalization. The Orthodox Church venerates him as a saint and confessor of the faith.