Family and Early Life
Constantine's father, Flavius Constantius (Constantius Chlorus), was a Roman army officer of Illyrian or Thracian background who became caesar under Diocletian and later augustus. His mother, Helena, is described as a woman of low social standing, possibly from Drepanum in Bithynia, later renamed Helenopolis; the New Advent encyclopedia characterises her as 'a woman of humble extraction but remarkable character and unusual ability.' Whether his parents were legally married or Helena was his father's concubine remains disputed.
Constantine received a formal education at Diocletian's court in Nicomedia and distinguished himself in early military service before joining his father in Britain. When Constantius died at York on 25 July 306, the troops proclaimed Constantine, and the OCA synaxarion relates that 'the future ruler of all the whole Roman Empire, was raised to respect Christianity.'
Rise to Power
Galerius initially recognised Constantine only as caesar, ruling Britain, Gaul, and Spain with one of Rome's largest armies. In spring 312 he moved against Maxentius, who controlled Italy and Rome. On 28 October 312 he defeated Maxentius at the Milvian Bridge, where his rival drowned in the Tiber, making Constantine master of the West.
According to several sources, the victory was preceded by a vision: Eusebius describes a cross of light with the inscription 'In this sign thou shalt conquer,' while OrthodoxWiki records 'a chi-rho in the sky, with the inscription By this sign shalt thou conquer.' Constantine completed his consolidation of power by defeating Licinius at Adrianople (3 July 324) and Chrysopolis, becoming sole emperor.
The Church and the Empire
The Edict of Milan, agreed with Licinius in 313, granted full religious tolerance to Christianity and all religions, legalised the Christian faith, restored property confiscated during Diocletian's persecution, and established Sunday as a day of worship. By 323–324, controlling the entire Roman world, Constantine extended these protections eastward, ending three centuries of Christian persecution.
Constantine granted the Church substantial privileges, including immunity from taxation for clergy, property inheritance rights, and ecclesiastical jurisdiction over certain matters. His legislation also improved protections for children, slaves, and women. The New Advent encyclopedia notes that his character holds genuine contradictions: generous to the point of prodigality in almsgiving and church adornment, yet capable of cruelty, having executed his brother-in-law Licinius, his son Crispus, and his wife Fausta.
In confronting the Arian controversy he 'avoided any direct interference with dogma,' deferring to synodal decisions. He convened the First Ecumenical Council at Nicaea in 325, attended by 318 bishops, which condemned Arianism, affirmed the divinity of Christ, and produced the Nicene Creed. He also commissioned the Church of the Holy Sepulchre in Jerusalem.
Foundation of Constantinople
Rather than maintain Rome as his seat, Constantine transferred his capital eastward to the ancient city of Byzantium. Rebuilt and officially styled 'New Rome' (Nea Roma), it came to bear his own name as Constantinople in his honour and served as the empire's capital for over a thousand years.
Veneration and Legacy
Constantine is venerated as a saint in Eastern Christianity, designated by the Church as Equal-to-the-Apostles. The Orthodox Church commemorates him on 21 May together with his mother, Saint Helen. The OCA synaxarion records that he 'accepted holy Baptism on his deathbed, having prepared for it all his whole life.' He is credited with transforming world history by giving Christianity a recognised and protected place within the Roman state, earning the title 'the Great.'
St. Nikodemos the Hagiorite affirmed that 'Constantine the Great always was a Saint and Equal to the Apostles, for so he was called in the Minutes of the Ecumenical Synods, as well as in the common and traditional glory of the Church.'
Relics & Shrines
Constantine was buried in the Church of the Holy Apostles in Constantinople. The OCA synaxarion records that relics are preserved at multiple locations, including Mount Athos, Cyprus, and Russian monasteries.