Constantine the Great: Rome’s Savior & Reformer

In all of history, few figures have reshaped the world as profoundly as Constantine the Great. Born amidst the chaos of a divided Roman Empire, Constantine emerged not only as a formidable warrior and shrewd politician but as the emperor who would forever alter the course of Western civilization. His vision went beyond mere conquest; he forged a new path for the empire, blending politics, religion, and culture into a legacy that still reverberates today. Constantine’s reign marked the dawn of a new era, one where the shadow of the cross loomed over the Roman world.

Constantine the Great and the Long Road to Greatness

Thanks to conflicting sources, we can’t be sure exactly when Constantine (or Gaius Flavius Valerius Constantinus, to give him his full name) was born. Estimates put the date at somewhere between 272 and 285 AD, at Naissus in present-day Syria.

His father was Flavius Constantius, later known as Constantius I, a high-profile military commander in the region and a member of Emperor Aurelian’s bodyguard. His mother, simply known as Helena, was a Greek Christian of low social standing, and it’s unknown whether she was married to Constantius or simply one of his concubines. The young Constantine benefited from a privileged upbringing but likely saw little of his father growing up.

Constantius appoints Constantine as his successor by Peter Paul Rubens, 1622 (Public Domain)

Still, thanks to nepotism, Constantine spent much of his young life in the imperial court. He earned a reputation as a hardworking and politically savvy young man. Under the emperor’s watchful gaze, he worked his way up and became the governor of under Diocletian in either 284 or 285 AD. Diocletian was somewhat of a role model to the young Constantine and taught him that the emperor’s job was to always act in the empire’s best interests.

Not long after promoting Constantine, Diocletian upset the status quo by announcing Maximian as his co-emperor. He gave Maximian the west and kept the east for himself. The Roman Empire still existed as a whole; Diocletian just thought having two emperors would make administration somewhat easier. As Emperor of the West, Maximian made Constantius his praetorian prefect in Gaul.

The bigger upset came in 305 AD when Dalmatia Diocletian and Maximian both decided to abdicate. They placed Galerius (an unpopular choice) on the throne in the east and Constantius in the west. The problem lay in the fact that Galerius appointed Maximinus Daia as his Caesar, and Constantius had Flavius Valerius Servius as his. This greatly upset both Constantine and Maxentius (son of Maximian), who had hoped to receive these roles for themselves. 

Battle of Constantine and Maxentius (detail of part of a fresco by Giulio Romano in the Hall of Constantine in the Raphael Rooms in the Vatican), copy c. 1650 by Lazzaro Baldi, now at the University of Edinburgh. (Public Domain)

While this new system of rule, the Tetrarchy, looked like a meritocracy, nepotism still ran deep. Ever since Constantius had been made Caesar in 293 AD, Constantine had been in Diocletian’s court, being groomed as his father’s presumed heir. 

After Diocletian abdicated, however, Constantine landed in Galerius’s court. Ancient sources make Galeirus sound like a barbarian and suggest Constantine wasn’t safe. Some claim Galerius sent Constantine out on suicide missions and gave him deadly tasks to complete (like fighting a lion to the death) in an attempt to get rid of him. The worst of these claims are probably pro-Constantine propaganda, but it’s clear that Galerius’ court wasn’t the best fit for Constantine.

In 306 AD, Constantine was allowed to leave the court of Galerius and join his father (either because Constantinus asked nicely or because Galerius wished to appease an upset Constantine). Either way, the result was almost a year of father-son bonding, during which the two campaigned in Britain against the troublesome Picts beyond Hadrian’s wall.

Then Constantius went and ruined things by dying of leukemia on July 25, 306 AD, in Eboracum. His last act was to appoint Constantine to the position of Augustus. Gaul and Britain accepted their new ruler, and Constantius’ loyal troops swore to follow him.

Not everyone was happy about it. Hispania rejected Constantine as their ruler (they had only recently been conquered), and Galerius was outraged. Technically, Constantine’s ascension had been illegal. Unfortunately for him, Constantine had proven himself since his father’s death by attacking and defeating the Franks, making his army even more loyal. In the end, Galerius decided on a compromise. He made Constantine Caesar and instead made his close friend, Severus, Augustus of the West. For their part, Constantine’s men ignored this and carried on calling him Augustus.

This new setup, however, upset Maxentius, who had now been overlooked twice. In October 307 AD, he took matters into his own hands and decided to declare himself Augustus. It was a ballsy move, but he had the backing of the people of Rome and the Praetorian Guard. Before things could get out of hand, Maximian came out of retirement and went to visit Constantine. If Constantine agreed to marry Maximian’s daughter, Fausta, and support his new brother-in-law, then Constantine would be made Augustus.

Maxentius, Constantine, and Maximian all united against Severus, whom no one trusted thanks to his close relationship with Galerius. This was unwelcome news for Severus, whose army promptly deserted him (they were probably bribed), forcing him to flee to Ravenna. He was then quickly captured and executed. This upset Galerius, who led a brief and unsuccessful invasion into the West.

The trouble wasn’t over yet though. In 308, a new tetrarchy was created. Licinius, another friend of Galerius, made Augustus, and Constantine stayed Caesar, meaning Maximian had reneged on their deal. 

Maximian then went one step further. In 310 AD, while Constantine was away fighting the Franks, Maximian came out of retirement again, declared Constantine dead, and made himself Augustus. When Constantine returned, he hunted his troublesome father-in-law to modern-day Marseilles, where Maximian hanged himself rather than be caught.

Back in Rome, Maxentius was losing favor. He had overtaxed the people so that he could build a new basilica and a massive statue of himself. Riots turned into revolts, and thousands of Romans were massacred in the streets. Constantine sat back and waited patiently, happy to watch Maxentius self-destruct. During this time, he sowed the seeds of the idea that it was his ancestral right to rule all of Rome and that it was time for the Tetrarchy to end.

In mid-310 AD, an ailing Galeirus called for an end to religious persecution and then died in 311 AD. With the tetrarchy all but destroyed, Constantine was free to raise an army of 40,000 and march across the Alps to invade Italy.

Becoming Emperor

Maxentius acted quickly after the death of Galerius to try and bolster his rule, but it was too late. He had too little support. In 312 AD, he left Rome to face Constantine at the Battle of Milvian Bridge. 

According to legend, the day before the battle, Constantine saw a cross of light in the sky with the words In Hoc Signo Vinces, “in this sign, conquer,” below it. He then dreamed that Jesus Christ himself came to him, telling him to bring the sign of the cross into battle. Constantine did just that, putting the cross on all his banners.

Fresco of Constantine I in the center, on the Battle of Milvian Bridge, the Vatican. (Daryl Mitchell /CC BY-SA 2.0)

Despite being severely outnumbered, Constantine’s army thrashed Maxentius.’ Maxentius attempted to flee to Rome, but before he could reach home, he fell into a river and drowned, likely crushed by his surviving men, who were also fleeing. Constantine took all of this as a sign and officially converted to Christianity. 

He then announced himself Augustus (again) and marched into Rome. As Augustus of the West, one of his first acts was to issue the Edict of Milan. This announced the toleration of all religions, especially Christianity. 

While this was going on, the East had its own problems. Following the death of Galerius, Maximinus and Licinius began fighting for control of the East. There was a brief peace after the two decided to split it between them, but they fell out again in 313 AD and went to war again.

Ultimately, Licinius came out victorious. Licinius did so by winning the favor of the Christians, whom Maximinus had promised to destroy. Maximinus ended up killing himself, and Licinius executed anyone who might be a danger to him, including the sons of Galerius and Severus, Maximinius’ whole family, and Diocletian’s daughter.

Now it was time for Licinius and Constantine to go to war. Up until 316 AD, they had held an uneasy truce thanks to Licinius’ tolerance of Christianity (he co-signed the Edict of Milan) and the fact he was married to Constantine’s half-sister. Exactly what caused them to go to war is unknown, but one of Licinius’ closest allies trying to assassinate Constantine probably didn’t help.

The two first fought at the Battle of Cibalae. It was an easy victory for Constantine. Their next battle, at Hadrianopolis, also went his way and resulted in land cessions to him.

Following the battle of Mardian in 317 AD, the two emperors decided to make peace. All this fighting was bad for the empire. It wouldn’t last long. In 320 AD, Licinius changed his mind about the Christians and began persecuting them, executing the worshippers, seizing their lands, and burning their churches. This made Constantine look bad, and he began raising an army, determined to put down Licinius the first chance he got.

Civil War broke out in 324 AD, and several large battles ensued, including a second at Hadrianopolis. In September of that year, Constantine defeated Licinius at Chrysopolis. Licinius surrendered and asked to be allowed to retire. Constantine agreed and allowed Licinius to go back to civilian life. Then he changed his mind and decided it would be better to hang Licinius and his 9-year-old son. 

Building Byzantium

It had been a long road, but at 52 years old, Constantine was finally Rome’s sole emperor. After years of unrest, the empire was united, and stability could resume. Yet there was a problem.

The city of Rome itself wasn’t the capital it had once been. Years of war and neglect had left it crumbling, and despite Constantine’s attempts at sprucing it up, he soon realized a new capital was needed. There weren’t any good options.

Nicomedia had been Diocletian’s capital, so that was out. The ancient city of Troy was an option but came with its own baggage. In the end, Constantine set his sights on Byzantium. 

This ancient city was on the European side of the Bosporus, meaning it was strategically located. It could look over the traffic to and from the Black Sea, and its harbor, The Golden Horn, was easy to defend. Even better, it wasn’t associated with any past emperors, and in its current state, it could be rebuilt in Constantine’s image.

The Colossal marble head of Emperor Constantine the Great, Roman, 4 th century, located in the Capitoline Museums in Rome. ( CC BY-SA 3.0 )

He brought in master craftsmen and artisans from across the empire to revitalize the city. Wide avenues with statues of great emperors like Alexander, Caesar, Augustus, and Diocletian were built. Even more statues of Constantine were placed all over the place. 

The city walls were rebuilt and fortified, cisterns were built, and churches like the Hagia Irene were dotted across the city. In a nod to religious freedom, pagan temples were also built. 

Constantine and Christianity

Constatine’s relationship with Christianity isn’t as clear-cut as it might seem. During his prolonged rise to power, he had always shown tolerance to Christians and pagans alike. While he had claimed to be Christian since 312 AD, some sources state he was only baptized on his deathbed. In his youth, he had openly worshiped the sun god.

His tolerance probably came from his mother, who was a devout Christian. After becoming Emperor, he sent her on a pilgrimage to the Holy Land, where she built Bethlehem’s Church of the Nativity. 

Some historians say Constantine made Christianity the empire’s official religion, while others say it was Theodosius. The truth seems to be somewhere in between. Constantine certainly favored the Christians and happily abolished crucifixions and banned gladiatorial contests. He also stopped pagan sacrifices, created laws against sexual immorality, and banned ritual prostitution. 

However, he tolerated most pagan practices and built pagan temples. Pagan symbols like Sol Invictus, and Mars also appeared on his coins. Constantine was a wise ruler and knew that persecuting pagans would make him look like a hypocrite and make him enemies he couldn’t afford to make.

A gold coin of “Unconquered Constantine” with the god Sol Invictus behind him, struck in AD 313. The use of Sol’s image stressed Constantine’s status as his father’s successor, appealed to the educated citizens of Gaul, and was considered less offensive than the traditional pagan pantheon to the Christians (Public Domain)

Still, Constantine saw himself as a Christian leader, and in 325 AD, he invited clerics from all over his empire to the Council of Nicaea. This massive event led to the condemnation of Arianism (the belief that Christ was not divine) and the creation of the Nicene Creed (the definition of what it means to be Christian). 

Death

The rest of Constantine’s reign was equally busy. In 332 AD, he had his son, Crispus, executed on charges of adultery. According to ancient sources, these charges came from Constantine’s second wife, Fausta, who was in love with Crispus. When the young man rejected her advances, she fabricated the charges as an act of revenge. After these charges were proven to be false, Fausta killed herself. Constantine never quite got over the guilt.

Gold coin of Constantine’s eldest son Crispus, who was executed by his father. Right: Bust of Constantine’s wife Fausta, in the Louvre, Paris (Public Domain, Louvre Museum/ CC BY 3.0)

Perhaps to distract himself, Constantine continued his role as a commander in the military. He led various successful campaigns, defeating the Alemannia in 328 AD and the Goths in 332 AD. His dream, however, was to defeat the Persians in a “Christian Crusade” after they invaded Armenia in 336 AD. He never got the chance.

In early 337 AD, Constantine became ill and realized the end was nigh. He called off his campaign and began preparing for his death. Constantine left his capital to visit the hot baths near Helenopolis (his mother’s city) in the hopes they might revitalize him. Instead, his condition grew worse, and he arranged to be baptized in the River Jordan, where it was said Christ was baptized.

Ancient sources claim Constantine died not long after being baptized in 337 AD. He was then buried at the Church of the Holy Apostles. His sons Constantine II, Constantius II, and Constans then took over the family business. Like their father before them, they disliked sharing power and soon fell out, sparking another war. Finally, Constantius II emerged victorious and became the new sole emperor.

Conclusion

Constantine’s journey to becoming the sole ruler of the Roman Empire was a long and arduous one, marked by years of fierce battles and political maneuvering. After securing his position, he ruled for over three decades, steering the empire through monumental changes. 

His reign saw the foundation of Byzantium, the future Byzantine Empire, and the elevation of Christianity from a persecuted faith to the empire’s dominant religion. Constantine’s legacy endured across the Christian world and the Eastern Roman Empire, reflecting the undeniable mark he left on history, both as a conqueror and as a visionary leader.

Top image: Statue of Constantine I, near York Minster, York, England.       Source: Son of Groucho / CC BY 2.0

By Robbie Mitchell