Constantine

"In this sign, conquer"

In 312 the Roman Empire was divided among rival emperors. Constantine the Great, son of a western emperor, had been proclaimed by his troops at York in Britain in 306. He marched on Rome to fight his rival Maxentius. On the eve of the battle, Constantine had an experience that changed history.

We have two accounts, and they differ. The Christian writer Lactantius, writing soon afterward, says Constantine was told in a dream to mark his soldiers' shields with a Christian symbol, probably the chi-rho (☧), the first two Greek letters of "Christ." Years later, Eusebius of Caesarea of Caesarea wrote that Constantine told him personally, under oath, that he and his army had seen a cross of light in the sky above the sun, with the words "In this sign, conquer." That night Christ appeared to him in a dream and told him to use the sign as a standard.

Whatever happened, Constantine fought under the Christian sign. On 28 October 312, at the Milvian Bridge over the Tiber, Maxentius' army was routed and Maxentius drowned. Constantine entered Rome as master of the West and gave the credit to the God of the Christians.

A real conversion?

Historians have argued for centuries about how sincere Constantine was. There are reasons for doubt:

• He kept the pagan title Pontifex Maximus (chief priest) and for years put the Sun god on his coins.
• He was not baptized until he was dying, in 337.
• He had his eldest son Crispus and his wife Fausta killed in 326, for reasons that remain mysterious.
• Christianity was politically useful: a growing, organized community across the empire.

But there are also reasons to take him seriously. Christians were still only perhaps 10 percent of the population, and mostly in the East, not in his western power base or his army. Backing them was a risk, not an obvious advantage. His letters show a genuine, if muddled, belief that the Christian God had given him victory and would punish him if the church was divided. Delayed baptism was common at the time (see Worship and Daily Life). Most historians now think Constantine sincerely believed in the Christian God, as a Roman would believe in a powerful patron deity, while understanding the faith imperfectly.

The Edict of Milan

In 313 Constantine met his eastern co-emperor Licinius at Milan. They agreed a policy, usually called the Edict of Milan, granting "to Christians and to all others full freedom to follow whatever religion each one wished." Confiscated church property was to be returned. This was religious freedom for everyone, not yet a Christian state. Persecution was over.

In 324 Constantine defeated Licinius and became sole ruler of the whole empire. From then on, his favor toward Christianity became more open.

From persecuted to official in 80 years

An emperor's gifts

Constantine poured imperial resources into the church:

• Buildings: He funded huge churches. In Rome he built the Lateran basilica (the pope's cathedral) and Old St Peter's over Peter's supposed tomb. In Jerusalem he built the Church of the Holy Sepulchre over the site of Jesus' tomb, identified by his mother Helena on her pilgrimage. Christians adopted the Basilica, a large Roman public hall, as their church design.
• Privileges: Clergy were exempted from expensive civic duties. Bishops could judge legal cases. Churches could receive inheritances.
• Laws: In 321 Sunday became an official day of rest. Crucifixion was abolished, and branding on the face was banned because the face bore God's image. Laws made it easier to free slaves in church.
• A new capital: In 330 he dedicated Constantinople ("Constantine's city," modern Istanbul) on the site of Byzantium. It was a "New Rome" with churches instead of pagan temples. It would be the capital of the Christian East for more than a thousand years (see Byzantium and the Icons).

The emperor and the church's quarrels

Constantine soon discovered that the church was not as united as he hoped. In North Africa, the Donatists had split from the mainstream over clergy who collaborated during persecution (see Augustine). In the East, a fierce dispute over the teaching of a priest named Arius was tearing churches apart. Constantine believed a divided church would anger God. So he did something new. He summoned and paid for church councils, and he sometimes enforced their decisions with exile.

In 325 he called bishops from across the empire to Nicaea, the first "ecumenical" (worldwide) council (see Arius and the Council of Nicaea). Eusebius describes the emperor entering the hall "like some heavenly angel of God, clothed in a raiment which glittered as it were with rays of light." The scene would have been unimaginable twenty years earlier, when bishops were being tortured.

After Constantine

Constantine's sons continued to favor Christianity, though they backed the Arian side in the doctrinal disputes. Then came a sudden reversal. In 361 his nephew Julian "the Apostate", raised Christian, became emperor and openly returned to the old gods. Christians called him "the Apostate." He tried to revive a reformed paganism, complete with charitable works modeled on the Christians'. He banned Christians from teaching classical literature. But he was killed fighting the Persians in 363, after reigning less than two years. A legend has him saying as he died, "You have conquered, Galilean."

The final step came under Theodosius I I. In 380 his Edict of Thessalonica declared that all peoples should follow the faith of the bishops of Rome and Alexandria, that is, Nicene Christianity. Other Christian groups were labeled heretics. In 391–392 pagan sacrifices were banned outright. Temples were closed or destroyed, sometimes by Christian mobs. In 393 the Olympic Games, a pagan religious festival, were held for what may have been the last time in antiquity. In less than a century, the persecuted had become the established, and sometimes the persecutors.

Triumph or fall?

Was Constantine the best thing or the worst thing ever to happen to the church? Christians have answered both ways.

• Triumph: Eusebius saw Constantine as God's chosen instrument, ending persecution and allowing the gospel to transform society. Byzantine and Orthodox Christians honor him as a saint, "equal to the apostles."
• Fall: Many later reformers, especially Anabaptists, saw the "Constantinian shift" as the moment the church sold its soul, swapping the cross for the sword and filling up with nominal members. Modern writers often use the word "Christendom" for the partnership of church and state that began here, which lasted in Europe until recent times.