Constantine the Great

The First Christian Emperor of Rome

Constantine. Hulton Archive/Getty Images

The Roman Emperor Constantine (c. 280 - 337 A.D.) was one of the most influential personages in ancient history. By adopting Christianity as the religion of the vast Roman Empire, he elevated a once illegal cult to the law of the land. At the Council of Nicea, Constantine settled Christian doctrine for the ages. And by establishing a capital at Byzantium, later Constantinople, he set into motion a series of events that would break the empire, split the Christian church and impact European history for a thousand years.

Early Life

Flavius Valerius Constantinus was born in Naissus, in the province of Moesia Superior, present-day Serbia. Constantine's mother, Helena, was a barmaid, and his father a military officer named Constantius. His father would rise to become the Emperor Constantius I (Constantius Chlorus) and Constantine's mother would canonized as St. Helena. She was thought to have found a portion of the cross of Jesus. By the time Constantius became governor of Dalmatia, he required a wife of pedigree and found one in Theodora, a daughter of Emperor Maximian. Constantine and Helena were shuffled off to the eastern emperor, Diocletian, in Nicomedia.

The Fight to Become Emperor

Upon the death of his father on July 25, 306 A.D., Constantine's troops proclaimed him Caesar. Constantine wasn't the only claimant. In 285, Emperor Diocletian had established the Tetrarchy, which gave four men rule over a quadrant each of the Roman Empire. There were two senior emperors and two non-hereditary juniors. Constantius had been one of the senior emperors. Constantine's most powerful rivals for his father's position were Maximian and his son Maxentius, who had assumed power in Italy, controlling Africa, Sardinia, and Corsica, as well.

Constantine raised an army from Britain that included Germans and Celts as well—Zosimus says it amounted to 90,000-foot soldiers and 8,000 cavalry. Maxentius raised his army of 170,000-foot soldiers and 18,000 horsemen. (The figures tend to be inflated, but they show relative strength.)

On October 28, 312 A.D., Constantine marched on Rome and met Maxentius at the Milvian BridgeThe story goes that Constantine had a vision of the words "in hoc signo vinces" ("In this sign you will conquer") upon a cross, and he swore that, should he triumph on that day, he would pledge himself to Christianity. (Constantine actually resisted baptism until he was on his deathbed.) Wearing a sign of a cross, Constantine indeed won. The following year, he made Christianity legal throughout the Empire (the Edict of Milan).

After the defeat of Maxentius, Constantine and his brother-in-law Licinius split the empire between them. Constantine ruled the West, Licinius the East. The two remained rivals for a decade of uneasy truces before the animosity boiled over and culminated in the Battle of Chrysopolis, in 324 A.D. Licinius was routed and Constantine became the sole Emperor of Rome.

A New Roman Capital

To celebrate his victory, Constantine created Constantinople on the site of Byzantium, which had been Licinius' stronghold. He enlarged the city, added fortifications, a vast hippodrome for chariot racing, a number of temples, and more. He also established a second Senate. When Rome fell, the capital of Constantinople became the de facto seat of the empire.

Constantine and Christianity

Much controversy exists over the relationship between Constantine, paganism, and Christianity. Some historians argue that he was never a Christian, but rather, an opportunist; others maintain that he was a Christian before the death of his father. But his work for the faith of Jesus was many and enduring. The Church of the Holy Sepulchre in Jerusalem was built on his orders; it became the holiest site in Christendom. For centuries, the Catholic Pope traced his power to a so-called Donation of Constantine (it was later proven a fake). Eastern Orthodox Christians, Anglicans, and Byzantine Catholics venerate him as a saint. His convocation of the First Council at Nicaea produced the Nicene Creed, article of faith among Christians the world over.

Death of Constantine

By 336, Constantine, ruling from his capital, had reclaimed most of the long-lost province of Dacia, lost to Rome in 271. He planned a great campaign against the Sassanid rulers of Persia but fell ill in 337. Unable to complete his dream of being baptized in the Jordan River, as was Jesus, he was baptized by Eusebius of Nicomedia on his deathbed. He had ruled for 31 years, longer than any emperor since Augustus.