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Constantine, the first Christian emperor
Ruled 306–337; Edict of Milan 313; Christianity made state religion 380 (Theodosius)· Founder, prophet or teacher· Judaism, Christianity & Islam
Historical recordConfirmed by archaeology, outside sources or contemporary records.
The Roman emperor who embraced Christianity, ended its persecution and set the empire on the path to becoming Christian.
See it on the World Religions map →What it is
Before the Battle of the Milvian Bridge in 312, Constantine reported a vision, and his soldiers marked their shields with a Christian symbol. He won and, with co-emperor Licinius, issued the Edict of Milan in 313, granting religious freedom and returning church property. He funded great churches, including Old St Peter's in Rome and the Holy Sepulchre in Jerusalem, convened the Council of Nicaea and founded Constantinople. He was baptized only on his deathbed in 337.
Why it matters
He turned Christianity from a persecuted minority into the emperor's favored faith. In 380 Theodosius made it the state religion, binding church and state together for centuries.
Life, legacy and sources
Eusebius' Life of Constantine and Lactantius, both contemporaries; the text of the Milan agreement; coins showing the Chi-Rho; the Arch of Constantine; surviving churches he founded.
Questions and debates
How sincere and how early his conversion was is debated: he kept the pagan title of chief priest and sun-god images on coins for years.
Inside this (1)
Connections (4)
▸Constantine, the first Christian emperor convened Council of Nicaea and the Nicene CreedHistorical record
The connection
The Arian dispute was splitting the church just as Constantine reunited the empire in 324. Wanting one church to match one empire, he summoned bishops to Nicaea, paid their travel, opened the council in person and urged agreement. He then exiled Arius and the bishops who would not sign, enforcing the result with imperial power.
When and where
Nicaea (İznik, Turkey), near his residence at Nicomedia, summer AD 325, with roughly 250–300 bishops, mostly from the East.
Historical evidence
Eusebius of Caesarea, who attended, describes Constantine's role; Constantine's own letters about the council survive.
Questions and debates
How far Constantine pushed the key term homoousios himself is debated; he later readmitted Arius and was baptized by an Arian-leaning bishop.
▸Constantine, the first Christian emperor began the end of Roman gods and state religionMostly agreed by scholars
The connection
Constantine did not ban the old gods, but he shifted money, prestige and legal privileges to the church, stripped some temples of treasure and, according to Eusebius, restricted sacrifice. His successors went further. Theodosius outlawed pagan sacrifice in 391–392, and by about 400 Rome's public state cults had largely ended.
When and where
Roman Empire, 312–337; continued by Constantius II's law against sacrifice (341), Gratian's removal of the Altar of Victory (382) and Theodosius' decrees. Emperor Julian briefly attempted a revival (361–363).
How do we know?
Imperial laws in the Theodosian Code, temple closures in the archaeological record, Eusebius' account, and pagan protests such as Symmachus' plea for the Altar of Victory (384).
Questions and debates
Whether Constantine himself banned sacrifice is debated; many historians stress that traditional worship faded gradually over two centuries rather than ending abruptly.
▸Constantine, the first Christian emperor founded Constantinople, later seat of Eastern Orthodox ChurchHistorical record
The connection
Constantine refounded the Greek town of Byzantium as Constantinople, his new Christian capital, in 330. Its bishop was ranked second only to Rome's in 381 and became the leading patriarch of the East. Orthodox Christians honor Constantine as a saint 'equal to the apostles', and the city remains the seat of their first-ranking patriarch.
When and where
Byzantium, on the Bosporus, dedicated May 11, 330; the patriarch of Constantinople still lives there, in Istanbul's Fener district.
Historical evidence
Roman histories, the canons of the councils of Constantinople (381) and Chalcedon (451) on the see's rank, and the patriarchate's continuous presence in Istanbul.
Questions and debates
How sincere and complete Constantine's own conversion was is debated; he was baptized only on his deathbed in 337, by a bishop later seen as heretical.
▸Constantine, the first Christian emperor legalized and favored ChristianityHistorical record
The connection
Constantine ended persecution in his lands, and the Edict of Milan (313) guaranteed Christians freedom of worship and returned their property. He then gave clergy tax exemptions, let bishops judge legal cases, built major churches and made Sunday a day of rest in 321. Under such patronage the church grew rapidly in the following decades.
When and where
Rome, Milan and Constantinople, 312–337. Emperor Galerius had already issued an edict of toleration in 311; Constantine became sole emperor in 324.
Historical evidence
Laws preserved in the Theodosian Code, Lactantius' text of the Milan agreement, Eusebius' writings, and surviving churches such as the Lateran in Rome.
Questions and debates
How much growth came from imperial favor rather than earlier momentum is debated; Christians were perhaps a tenth of the empire's people in 312, an estimate.