Constantine and the Conversion of the Roman Empire

This post is a preview of a forthcoming online Davenant Hall class, “Constantine and the Conversion of the Roman Empire”, running in the Winter Term 2024 (January to March), and convened by Dr. Matthew Hoskin.

If you wish to register for the module you can do so here.

It has been popular, especially since the early 2000s and Dan Brown’s The Da Vinci Code, to question the truth of Constantine’s conversion to Christianity. Many believe that he was really a crypto-pagan all along and that his motivation was all about power–indeed, some who doubt that he was really a pagan are convinced that his support of Christianity was about power. This version of history claims that he saw the failing empire of Diocletian and his father Constantius and latched onto Christianity with its emphasis on unity, its network of bishops, and its similarities to solar monotheism (his “real” religion, if any). He seized the Christian religion as the new glue to hold the Roman Empire together and save it from ruin.

And then, in the Dan Brown version, Constantine crushes the voices of true Christianity–Gnostics–and suppresses dissent by establishing the canon of Scripture at Nicaea and outlawing Gnostics as part of his bid for power. In the process, he made Jesus a god, something previously unheard of.

All of the above is pretty much false–and that last paragraph utter bosh.

To disprove theories about Nicaea and Gnosticism, one need only read the various accounts of the council (including those by attendees Eusebius and Athanasius), its dogmatic decree, and its canons. None of this comes up. The canon of Scripture seems to have already been set informally, and it is very clear that the divinity of Christ has a strong ante-Nicene precedent that was clarified in the fourth century. In fact, this clarification went in a direction that Constantine would not have chosen himself (for his own early theology, see the letter to Alexander and Arius and his Oration to the Saints from just before the council).

What about the truth of his conversion? Was he really a pagan all along? How can we know? There are many pieces of evidence for Constantine’s Christianity. In 306, when he was master of Britain, Gaul, and Spain, he had already granted freedom of religion in his provinces. In 310, he had an experience that he considered a vision from a god, the first description of which is in a panegyric of 310, and which gets a Christian interpretation from him around 312. This interpretation was repeated by two people who knew him: Lactantius, his son’s tutor, and Eusebius, who met him at least once (and was, admittedly, his biggest fan). This Christian interpretation of the vision would lead to a symbol called the Labarum which Constantine placed on his standards, his coins, and his palace, based around the cross and the chi-rho Christogram. He produced many laws in East and West that favored Christians, such as bishops only being allowed to be tried by other bishops. He also outlawed public pagan sacrifice. When he conquered the eastern portion of the Roman Empire in 324, he brought with him western Christian traditions such as Lent and went on a dramatic Christianization from then until his death in 337.

All of the above evidence is attested in the ancient sources, but the simplest way to prove he was a Christian would be to point to the letters and speeches of Constantine himself–authentic correspondence preserved by Eusebius of Caesarea in the Life of Constantine and in an appendix to the anti-Donatist work of Optatus of Milevis as well as Constantine’s own speech the Oration to the Saints. These straightforwardly demonstrate that Constantine considered himself a Christian.

Another variety of doubter questions whether Constantine was “really” a Christian because “real” Christians don’t exile people over theology or execute their sons for treason. As a historian, all I can say to that is that Constantine professed himself a Christian and pursued imperial policies that favored Christianity. That is enough definition for me. As a Christian, I admit to not being able to see someone else’s inner life. My broad take on his conversion is that between 310 and 312, Constantine threw in his lot with the Christian God and became a disciple of Jesus. Like all disciples, he would be a work in progress until his death in 337. As a public figure, his failures were more visible. Failure and sin do not equal insincerity nor are they evidence that someone is not “really” regenerated in Christ. If so, we are all damned.

All of this is to say: Constantine converted to Christianity. The full proof is found in the sources students will read with me in my upcoming course “Constantine and the Conversion of the Roman Empire”–Lactantius’ On the Deaths of the Persecutors, Eusebius’ Life of Constantine, laws of Constantine, panegyrics praising the emperor, his own letters and the speech mentioned above, a text called the Orio Constantini Imperatoris (aka Anonymus Valesianus I). These will open up not only the truth of his conversion but its results, which are much more important to us today and also much more interesting.

Constantine’s conversion had a profound influence on his religious policy and then on down through his successors for centuries through the Middle Ages to today in one way or another. Does your church enjoy tax-free status? Thank Constantine. Besides looking at Constantine’s own policies, this course will consider briefly the fourth-century solidifying and his legacy through his sons and then the resistance of Julian, the last pagan emperor, and then close with the reign of Theodosius I. Their religious policies will also be considered through surviving laws, the writings of Athanasius, Julian himself, and the debate over the Altar of Victory in the Senate House in Rome involving Ambrose and Symmachus, Ambrose’s On the Death of Theodosius, and more.

This wealth of fourth-century texts and documents will help us see how the Later Roman Empire was transformed and what exactly the pro-Christian emperors did. Today, the church of the West finds herself the most marginal she’s been since before Constantine. As some today seek a louder, clearer, and stronger voice for the church, what can these emperors and bishops tell us? In my upcoming Davenant Hall course, “Constantine and the Conversion of the Roman Empire”, we will explore answers to this question and more. Come, study with me this coming term at Davenant Hall!

This Christian History course will be taught by Dr. Matthew Hoskin. This course will run from January 8th through March 16th. Register here.

Dr. Matthew Hoskin (PhD University of Edinburgh) is a specialist in the history of ancient and medieval Christianity, especially the early Latin theological tradition, canon law, and manuscripts. In 2022, he saw the fruit of 10 years of research with the publication of his book The Manuscripts of Pope Leo the Great’s Letters (Turnhout, Brepols). While the Later Roman Empire may be his favourite place to do research, he has an enduring interest in medieval Britain and Ireland, and he has published about the influence of Boethius’ ideas on Tolkien’s The Lord of the Rings. He lives in Thunder Bay, Ontario, with his wife and sons in a house bursting with books and toys (many of which are his own).


Related Articles


Other Articles by

Augustine the Preacher

You know Augustine the theologian. Why not get to know Augustine the preacher?

Join our Community
Subscribe to receive access to our members-only articles as well as 4 annual print publications.
Share This