The thirty-third bishop of Rome, Sylvester was consecrated January 31, 314 and was buried December 31, 335, having completed nearly 22 years as head of the Church at Rome. A native Roman, Sylvester's parents were Rufinus and Justa. Legend has it that he was ordained by Pope Marcellinus before the Diocletian persecutions began. Later, he was attached to the papal court of Militiades.
Constantine and Licinius, co-emperors, had just signed the Edict of Milan, as it is called, to give Christians rights of property and worship, in the year before Sylvester became bishop. He was consecrated in the midst of great hope for the beleagured Christians.
However, there was still some left-over problems from Militiades' papcy which would not go away, the problem of the Donatists. these people were unwilling to forgive the lapsi, who, to save their lives during the persecutions of 303-308, lapsed from their faith. When the lapsi wanted to return to the Faith, the Donatists would not let them in. This lead to there being more than one bishop in some locations, an orthodox and a heretic Donatist. The Bishop of Rome did not have a centralized control of the Church at this time, so the Donatists turned to Constantine as the one to whom grievances should be addressed. The emperor established several councils, one in Rome, 313, and one in Arles, 314, both of which failed to satisfy the problem and the heresy remained active, especially in north Africa.
The far worse problem that Sylvester had to deal with was the Arian heresy. This was prevalent by 318, stirred up by a priest, Arius, of Alexandria. He insisted that Jesus, the Son, was not equal with God the Father, nor was he eternal, but that the Son had a beginning, unlike the Father. Constantine called for another council, this one at Nicea. Three hundred bishops attended, but only a few from the West, seeing as how traveling was still very difficult. Sylvester claimed old age as a reason to not attend and sent two legates, Vitus and Vincentius, who were given much honor and respect as his representatives. Of all the bishops, only 17 tried to defend the heresy, the rest voting to condemn it. At the same time, they developed another controversy: What was the formal nature of Jesus viz God the Father? Our Nicene Creed uses the Greek term homoousious, or "same essence", the same term adopted by the council. Many bishops signed the authorization, but the two papal legates signed last, indicating that their representation of the Bishop of Rome meant little. However, Sylvester never spoke against the Creed, implying that he supported it.
In addition to the large theological arguments going on, Sylvester and Constantine contributed greatly to the building of churches in Rome. Once the Lateran Palace had been donated to the Church of Rome, becoming the living quarters of the popes for 800 years, a bascilica and baptistry were added. The bascilica of the Sessorian palace (Santa Croce) was built. The first St. Peter in Vatican is from then. A presbyter named Equitius built a church on land he owned.Parts of the original Church of Equitius still exist. Also, Sylvester had a cemeterial church built over the catacomb of Priscilla, where he was eventually buried.
Regarding liturgical developments, it appears that Sylvester started a Roman school of singing, teaching liturgical music. This is also about the time that the first martyrology was drawn up.
There was a legend that was promulgated in the ninth century, on, based on a forged "memoir" of Constantine. It claimed that he had given Sylvester, personally, control of the Western empire, including the Italian peninsula and the city of Rome, primacy of all other bishops in the West, plus those of Antioch, Alexandria, Constantinople and Jerusalem. Not knowing it was a forgery, some of the popes used this Donatio to further their temporal power. By the time it was identified as a forgery, in the fifteenth century, the Church was a temporal and a spiritual power.
By the time Sylvester died, the face of the Church had changed greatly. It had power and control, property and people, more than ever before in its history. Thus began its rise to the most important organization in the world.