By Bart D. Ehrman, The University of North Carolina, Chapel Hill
The debate over whether Constantine had a sincere religious conversion started in 1853, with a Swiss scholar named Jacob Burckhardt, in a book written in German whose English title is The Age of Constantine the Great. Burckhardt’s overarching thesis was that Constantine’s conversion was not driven by deep religious persuasion or zeal but by what he termed a consuming lust for power.

Megalomaniac or Devout Christian?
As Burckhardt explicated the thesis, he argued that Constantine realized that the burgeoning Christian church could assist him in reaching his megalomaniacal goals, and so he forced an alliance with it out of personal ambition. Personally, he could not have cared less about the church and its truth claims.
This was obviously a revolutionary thesis, and it generated an enormous amount of debate. Supporters of Burckhardt’s basic thesis could point to a lot of interesting evidence, much of it still cited by advocates of the view today.
Continued Support to Rival Gods
To begin with, and somewhat shocking to many Christians who learned this for the first time, Constantine continued to embrace pagan views in the public eye. He made no attempt to rid the world of traditional pagan religions. That might seem odd enough to many Christians; if he were really Christian, if he truly believed the gospel message, wouldn’t he want everyone under his rule to accept it as well, knowing that if they didn’t, they would be damned to hell?

But there’s more to it than that. Constantine actually appeared to support pagan deities even after his alleged conversion, and he used his imperial power to promote them. One way to see this is by considering the public image he projected.
A Proof of Constantine’s Support
Back in antiquity, when most people were illiterate, the best and most widely used form of political propaganda used by the emperor was, oddly enough, the coins that were issued. These were available to everyone, and the images displayed on the coins communicated what an emperor wanted their subjects to think about them.
It’s no doubt significant that in 310 CE, Constantine started to have his coins printed with the image of Sol Invictus: the pagan unconquered sun god. But more striking is that coins issued long after his conversion continued to portray Sol Invictus. If Constantine was a Christian, why would his coins celebrate specifically a pagan divinity?
This article comes directly from content in the video series The Triumph of Christianity. Watch it now, on Wondrium.
Not Very-Christian Laws
Much of the legislation that Constantine enacted seemed to be the antithesis of Christian principles. It’s important to remember that legislation issued from Rome was rarely directed to the entire empire. Laws were issued for certain places and certain conditions, and it was usually impossible to enforce them. But the laws Constantine issued do show something of his temperament and mindset.
We can find the following penalties for illegal activity in the Roman legal compendium called the Theodosian Code, a collection made of laws starting with Constantine. It’s true that most of these laws were meant to promote social decency and to advance basic principles of morality, but the punishments!
Here are some of Constantine’s own laws as still recorded for us. Imperial bureaucrats who accepted bribes were to have their hands cut off. Guardians of girls who had been seduced were to have molten lead poured down their throats. Tax collectors who treated women tax-delinquent rudely were to be done to death with exquisite tortures. Anyone who served as an informer was to be strangled, and the tongue of envy cut off from its roots, plucked out.

Slaves who informed on their masters were to be crucified. Anyone guilty of parricide, “Shall not be subjected to the sword or fire or any other customary penalty, but he shall be sewed in a leather sack and confined within its deadly closeness he shall share the companionship of serpents.” And then thrown into a river or the ocean so that “while still alive, he may begin to lose the enjoyment of all the elements.” Do these seem like the rulings of a committed Christian?
Baptized on His Deathbed
The final argument against the legitimacy of Constantine’s conversion is the fact that even though he claimed it happened in 312 CE, he did not actually get baptized as a Christian until he was on his deathbed in 337, 25 years later. Is that plausible if he had actually committed himself to Christ and the Christian church?
These are indeed intriguing pieces of evidence. And it’s easy to see why scholars originally found them convincing and why some people still do.
Common Questions about Why People Doubt the Sincerity of Constantine’s Conversion
A book published in 1853 and written by Jacob Burckhardt was the start of the great debate over how sincere Constantine’s conversion to Christianity really was and whether it could have been a political ploy.
The image that Constantine had printed on coins after 310 CE was of Sol Invictus, a pagan god.
The Theodosian Code was a legal compendium, a list of laws that started with Constantine himself. The problem wasn’t the laws themselves, but the punishments were severe enough that Christians today might question the legitimacy of Constantine’s conversion. Punishments such as cutting the hands off of those who accepted bribes, torturing rude tax collectors to death, and crucifying slaves who informed on their masters.