Bishops of Rome under Constantine the Great

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.

In reality, Constantine was baptized (nearing his death in May 337) by Eusebius of Nicomedia, who, unlike the pope, was an Arian bishop of Constantinople.

Constantine's legalization of Christianity, combined with the donation of these properties, gave the bishop of Rome an unprecedented level of temporal power, for the first time creating an incentive for secular leaders to interfere with papal succession.

In spite of the Diocletian Persecution, Christians constituted approximately one-tenth of the population of the Roman Empire at the time of Constantine's rise to power.

It was without any single dominant ruling officer, its elders or leaders sharing responsibility, but distributing tasks, like that of foreign correspondent.

After the Edict of Milan, the church adopted the same governmental structure as the Empire: geographical provinces ruled by bishops.

Whatever his personal beliefs, Constantine's political interest in Christianity was as a unifying force and his policy of "the imposition of unity on the churches at all costs" soon set him on a "collision course with the popes.

[8] Silvester would have viewed Arianism as a heresy;[9] Constantine himself probably did not understand the complex theological issues in dispute, although he had surrounded himself with many followers of Arius, including Bishop Eusebius of Nicomedia, his eventual baptizer.

[10] The chief supporter of the Nicene Creed was Bishop Athanasius of Alexandria, but in 335 he was deposed and exiled to Gaul over unrelated fears about the Egyptian corn supply to Constantinople.

[10] Under Pope Liberius (352-366), the Arian conflict between the emperor and bishop of Rome culminated in the Synod of Arles (353), convened by Constantius II.

[13] The text says that all of these events occurred right after Constantine's entry into the city following the Battle of the Milvian Bridge, despite the fact that Silvester I did not become bishop until 314.

[13] John Malalas further embellished the story in his Chronicon, which claimed that Silvester I baptized not only Constantine, but his mother Helena, and—for good measure—a large group of his relatives and Roman bystanders.

[12] When Pope Sixtus V erected the Egyptian obelisk to the north of the Lateran Basilica in 1588, he added to the base the inscription "Constantine was baptized here.

[12] Depictions include the Stavelot Triptych (c. 1165), frescoes in I Santi Quattro Coronati, stained glass in the St Michael and All Angels' Church, Ashton-under-Lyne, and—most famously—Raphael's The Baptism of Constantine in the Raphael Rooms of the Apostolic Palace.