Constantine I: Contributions to Christianity and Other Accomplishments

From the lecture series: The Roman Empire: From Augustus to the Fall of Rome

By Gregory S. Aldrete P.h.D., University of Wisconsin, Green Bay

Roman emperor Constantine’s victory at the Milvian Bridge in 312 AD and the accompanying conversion to Christianity is considered to be one of the crucial events in Western history. Yet, the genuineness and completeness of Constantine’s conversion has been under scrutiny for several centuries now. Why?

Photograph of the ceremonial ‘Arch of Constantine’ in Rome.
The ceremonial ‘Arch of Constantine’ in Rome was built to commemorate Constantine’s victory after the Milvian Bridge battle. (Image: ArtRomanov/Shutterstock)

Constantine I was one of the famed emperors of Rome and the first to profess Christianity. He ruled during the 4th century, and some of his important accomplishments include his support of Christianity, construction of the city of Constantinople, and the continuance of the reforms of Diocletian.

Constantine and Christianity

Constantine’s adoption of Christianity marked the transformation of Christianity from an obscure sect to a dominant religion. By embracing Christianity, which was monotheistic in nature, Constantine introduced a notion that the one and only legitimate God had chosen him as the sole contender for the throne. Apart from having significant political ramifications, the idea also signaled an important shift in the relationship between emperors and the divine. In a period when there were multiple contenders for the imperial throne, this convenient philosophy made the rival claimants illegitimate and ensured Constantine’s authority.

Constantine’s Sincerity in Conversion

Throughout his early career, Constantine seemed to have been strongly drawn to the idea of aligning himself with a deity who took a personal interest in his success. Initially, these assertions centered around the sun god in his manifestation as Sol Invictus, the ‘unconquerable sun’. It was also a deliberate attempt to motivate his troops by using his association with Sol Invictus or ‘the unconquerable’.

Constantine’s victorious Milvian Bridge battle in 312 AD
Constantine claimed that a Christian God promised him military victory before the Battle of the Milvian Bridge in 312 AD. (Image: Giulio Romano/Public domain)

Later, in 310 AD, he claimed to have had a vision of Apollo promising him victory, an event that he commemorated on coins. A similar claim of manifestation by a Christian God before the Battle of the Milvian Bridge has led to a debate among the scholars. While some argue that these visions were cynical inventions of Constantine to inspire his soldiers before crucial military invasions, others argue that Christianity was just a minor cult at the time of Milvian Bridge battle and if Constantine was calculative, he would have chosen a more popular God for his vision. The obscurity of Christianity in his times and the fact that Constantine remained Christian for the rest of his life were the arguments supporting genuineness of his conversion.

This is a transcript from the video series The Roman Empire: From Augustus to the Fall of Rome. Watch it now, on Wondrium.

Contradictions of Constantine, the Christian

Constantine, however, continued to take some actions that seemed at odds to his idea of being a Christian. For instance, even a decade after his conversion to Christianity, Constantine kept minting coins that depicted images of traditional Roman gods and his favorite pagan god, Sol Invictus. He continued to subsidize the pagan temples from the imperial treasury and took control of the office of the Pontifex Maximus—the chief priest of the Romans who presided over rituals performed to the traditional pagan gods. He also consulted a pagan oracle when his capital city was struck by lightning.

Furthermore, Constantine espoused a cautious approach in his public promotion of Christianity. For instance, to commemorate the victory after the Milvian Bridge battle, he constructed a triumphal arch at Rome; yet, the inscription on ‘The Arch of Constantine’ does not specifically mention Christianity but instead attributes the victory to an unnamed ‘divine power’ and ‘the greatness of Constantine’s mind’.

Constantine waited until a little before his death to get baptized. While such delayed baptism was a common practice at the time, his dedication to the religion has been under question time and again.

The image of a golden medallion of 315 AD shows Constantine holding up the usual ruler’s scepter, which is in the shape of a cross. While the emperor’s helmet is decorated with the Christian Chi-Rho symbol, his shield bears the wolf who nursed Romulus and Remus. Constantine also presented himself as clean shaven, the first emperor to do so in several centuries. This was a deliberate attempt to portray him as different from others. Thus, with Constantine, the Roman Empire incorporated religion into the state and strengthened itself. For Constantine, Christian monotheism was just a means to an end, a legitimization of his vision of sole emperorship.

Learn more about early christianity.

Constantine, the Interventionist

Constantine seemed to be drawn to the political corollaries of a monotheistic religion since it offered a way to quash political division; but he then seems to have extended this idea to religion itself, deciding that it was a bad thing for there to be any religious factionalism among Christians. Therefore, he took an active role in attempting to resolve several purely theological disputes that threatened to fracture the early Christian community.

Portrayal of Constantine I with the bishops at the First Council of Nicaea in 325 AD.
Constantine I presided over the meeting of the bishops
at the First Council of Nicaea in 325 AD.
(Image: Unknown author/Public domain)

In the May of 325 AD, he presided over a meeting of over three hundred bishops at the Council of Nicaea. The council debated on the divine status of Jesus and instituted the document called Nicene Creed, a statement of the Orthodox Church to deal with certain voices of dissent. The key line of the Creed declares that Christ, God, and the Holy Spirit “contain the same divine essence”, and to this day, this remains core doctrine of the Catholic Church.

More than being just a leader of the Church, Constantine even seems to have viewed himself as the equivalent of an Apostle. He built a basilica containing statues of the traditional 12 apostles and in their center left a niche for a statue of himself. 

Learn more about early Christianity and the rise of Constantine.

Constantinople, the Eastern Capital

One of the most significant achievements of Constantine was the construction of the impressive city of Constantinople to serve as the eastern capital of the empire. He selected the old Greek colony of Byzantium and completely rebuilt it into a spectacular new capital, and named it after himself, Constantinople. The ancient city is located in modern-day Turkey and now known as Istanbul.

The grand new eastern capital of Constantinople was officially dedicated on May 11, 330 AD. It was endowed with the same features as the western capital of Rome and included a grand palace, an amphitheater, a hippodrome for chariot racing, a senate, and libraries. The city was divided into fourteen districts, and Constantine resided there for most of the rest of his reign.

The eastern capital was strategically located to overlook and control Bosphorus, the narrow strait which linked the Mediterranean Sea to the Black Sea. The natural harbor coupled with the geographical position between Europe and Asia soon turned Constantinople to a thriving port city. It was also situated on a highly defensible peninsula of land surrounded by water on three sides. Moreover, the massive concentric walls around Constantinople were so impervious that it could fortify the city from assaults for over 1,000 years.

Constantine was so much in love with the city that he shamelessly looted existing cities and monuments to beautify his new capital. He even went to the extent of moving the sacred tripod and statue of Apollo from the hallowed Greek Sanctuary of Delphi to the new capital. He also constructed a number of important churches in the city, including the first version of the Hagia Sophia.

Embracing the Diocletian’s Reforms

Not only did Constantine enthusiastically embrace most of the reforms, he went one step ahead to develop, strengthen, and further institutionalize them. Dismayed by the existing system, he was keen to refine and reform certain regular measures, thus laying the foundation for a model government that future emperors would follow.

He considered reforms in the military an important necessity and restructured the military, with emphasis on increasing the size and role of mobile cavalry forces. And though he continued with the old economic policies, he made concerted efforts to stabilize the currency. He also increased the number of senators to improve administration, but blurred the previous distinctions between senators and equestrians.

Although all of Constantine’s policies were very effective, he cannot be considered as a revolutionary as he was merely following precedent. Yet Constantine wanted to rule alone and did not make any effort to revive the tetrarchy system created by Diocletian. He rejected the tetrarchy system as the succession principle and recommended the concept of hereditary succession. Further, his belief in Christian monotheism provided a justification for his vision of sole emperorship.

Learn more about Diocletian and Late 3rd-Century Reforms

Common Questions about Constantine I

Q: How and when was the annual date for Easter celebration set?

Constantine summoned the Council of Nicaea and set the official procedure which determines the annual date when Easter is to be celebrated. This procedure is followed to this date by Christians.

Q: What was the Donatist dispute during the reign of Constantine?

Donatist dispute was a schism over whether the clergy could be forgiven for their fault, return to their faith, and again perform the sacraments. Constantine tried to intervene in one such debate, but failed to make peace between the quarreling factions.

Q: What is the Arch of Constantine?

The Arch of Constantine is one of the few triumphal arches constructed at Rome. It was for the first time that a monument was erected to celebrate the victory over fellow Romans, rather than foreigners.

Keep Reading
How Did Constantine Alter the Course of the Roman Empire?
Augustus: Paving the Way for Hereditary Succession
The Making of Constantinople: Constantine’s “New Rome”