Few events in the history of civilization have proved more transformative than the conversion of the emperor Constantine to Christianity in the year 312 CE. Later historians would sometimes question whether the conversion was genuine. But to Constantine himself and to spiritual advisors close to him, there appears to have been no doubt. He had shifted from one set of religious beliefs and practices to another. At one point in his life he was a polytheist who worshiped a variety of pagan gods—gods of his hometown Naissus in the Balkans, gods of his family, gods connected with the armies he served, and the gods of Rome itself. At another point he was a monotheist, worshiping the Christian god alone. His change may not have been sudden and immediate. It may have involved a longer set of transitions than he later remembered, or at least said. There may have been numerous conversations, debates with others, and reflections within himself. But he dated the event to October 28, 312. At that point he began to consider himself a Christian.1
The results were tremendous, but not for the reasons often claimed. It is not that Constantine eventually made Christianity the state religion. Christianity would not become the official religion of Rome until nearly eight decades later, under the reign of Emperor Theodosius I. And it is not that Constantine’s conversion was the single decisive turning point in the spread and success of the Christian religion, the one moment that changed all history and made the Christian conquest a success. At the rate it was growing at the time, Christianity may well have succeeded otherwise. If Constantine had not converted, possibly a later emperor would have done so—say, one of his sons. Instead, what made Constantine’s conversion revolutionary was that the imperial apparatus that before then had been officially opposed to Christianity and worked hard, in some regions of the empire, to extirpate it completely suddenly came to support it, promoting Christianity instead of persecuting it. Constantine did not make Christianity the one official and viable religion. He made it a licit religion, and one that enjoyed particular, even unique imperial privileges and funding. This support did indeed advance the Christian cause. The recognition that this faith was now favored from on high appears to have contributed to the already impressive numbers adding to the growth of Christianity, including the conversion of increasing numbers of imperial and local elites whose resources had until then funded (and thus made possible) the religious practices of their pagan world.
As important as Constantine’s conversion was to the welfare of the Christian movement, it is surprisingly difficult to describe what he converted from. Modern historians of religion who speak of conversion can mean a variety of things by it.2 Possibly it is simplest to keep the meaning broad and use the term to refer to a decided shift away from one set of religious practices and beliefs to another. That certainly happened with Constantine. At a moment that seemed, at least later in hindsight, to be clear and well-defined, he stopped being a pagan and became a Christian.
Conversion was not a widely known phenomenon in antiquity. Pagan religions had almost nothing like it.3 They were polytheistic, and anyone who decided, as a pagan, to worship a new or different god was never required to relinquish any former gods or their previous patterns of worship. Pagan religions were additive, not restrictive.
Christians, on the other hand, did require a choice. Converts were expected to forgo the worship of all the other gods and revere the Christian god alone. Only Judaism had similar expectations and demands. Among pagans—that is, among the 93 percent or so of the world that by custom, habit, and inclination worshiped multiple gods—worshiping a range of divine beings was not a religion that anyone chose. It was simply what people did. Being a pagan meant participating in the various religious activities associated with the official state gods, local municipal gods, personal family gods, and any other gods that were known to be involved with human experience. For everyone except Jews, and then Christians, this was more a way of life than a conscious decision. It was a matter of doing what everyone had always done, very much like participating in the life of the local community, with the exception that most people were involved with only one community but could be engaged in the worship of a virtually incalculable number of gods.
For that reason paganism should not be thought of as a solitary “thing” but as hundreds—thousands—of things.4 Those who practiced traditional religions—in other words, just about everyone—would never have recognized themselves as participating in something called “paganism” or, indeed, any kind of “ism.” There was not a thing there, nothing that could be named so as to sum up the totality of all the non-Jewish religious observances or beliefs or cultic practices of prayer and sacrifice ubiquitous in the culture. No pagan would have understood what it would mean to call themselves pagan. They were simply acting in time-honored ways of worshiping the gods.
Constantine, like everyone else who was not raised Jewish or Christian, participated in this worship. But he gave it up to follow the one god of the Christians. The narrative of how Constantine became a Christian is both intriguing and complex. It involves issues that we today would consider strictly social and political and other issues that we would consider strictly religious. But in the early fourth century—as in all the centuries of human history before that time—these two realms, the sociopolitical and the religious, were not seen as distinct. They were tightly and inextricably interwoven. On just the linguistic level, there were no Greek or Latin terms that neatly differentiated between what we today mean by “politics” and “religion.” On the practical level, the gods were understood to be closely connected with every aspect of the social and political life of a community, from the election of officials, to the setting of the annual calendar, to the laws and practices that governed social relations, such as marriage and divorce, to the administration of civil justice, to the decisions and actions of war, to all the other major decisions of state. The gods were active in every part of social and political life, and the decisions made and actions taken were done in relation to them.
On the imperial level this meant that it was widely known—and genuinely believed by most—that it was the gods who had made the empire great. The empire responded by sponsoring and encouraging the worship of the gods. Doing so would promote the commonweal. There was no sense that there was, should be, or could be a separation of church and state.
Starting in the mid-third century, the emperors themselves sensed this full well and acted accordingly. That is why, some years before Constantine converted, the Christian religion had been persecuted by order of the state. The Christians refused to worship or even acknowledge the gods of the empire, claiming in fact that these were evil, demonic beings, not beneficent deities that promoted the just cause of the greatest empire the world had ever known. The refusal to worship was seen by others to be dangerous to the well-being of the empire and thus to the security of the state. And so the decision to persecute—which seems to us, perhaps, to be a strictly religious affair—was at the time inherently sociopolitical as well. The Christians were to be removed like a cancer from the body politic. No emperor came to believe this more firmly—in no small part because of the alarming growth of this cancer—than Constantine’s predecessor on the throne, Diocletian, who instigated the most vicious empire-wide persecution ever seen. Constantine himself was later to rescind the demands of this persecution. But while it was still in process, he converted.
This conversion proved to be a linchpin of imperial history, not just for the fate of the Christian religion but also for the workings of the Roman state. We will look at the persecution of Diocletian in a later chapter, and at the broader biography of Constantine in another. For now, we are interested specifically in his conversion and how it radically changed the balance of power, both for the persecuted Christians and for the running of the Roman government. To make sense of the conversion we need to understand some of the political and religious backdrop to the story.
By the end of the third century CE, the empire was too vast and complex to be ruled by one emperor. It reached from Britain to Iraq and entailed virtually all areas connected to the Mediterranean, north into modern Europe, south into North Africa and Egypt, and east into Palestine and Syria, all the way to Persia. For many years it had been riven by internal disputes and foreign invasions. The year 284 CE is usually cited as the end of the major upheavals collectively known as the “Crisis of the Third Century,” a half century filled, internally, with imperial assassinations and usurpations involving some twenty-one legitimate emperors and thirty-eight usurpers. In addition, the empire had, for a time, been fractured by two breakaway states, one in the far west and one in the east. These had literally fragmented the empire and made the actual “Roman” state a slice of its former self. That is not to mention the incursions on the northern borders by barbarian hordes.5
The brilliant emperor-general Aurelian (ruled 270–75 CE) had defeated and reintegrated the breakaway states, but it was not until the reign of Diocletian that a fuller sense of order was restored internally, and with it a relatively secure border on the frontier. Diocletian was one of the truly great political administrators of Roman antiquity. His predecessors, including Aurelian, had never managed to bring any semblance of stability: Diocletian’s eight immediate predecessors had all been murdered, some of them within weeks or even days of taking the throne. He himself was to enjoy a reign of over twenty years. Diocletian was the first emperor of Rome to abdicate voluntarily.
Diocletian is best known to casual readers of Roman history as the great persecutor of Christians. This he certainly was, as we will see more fully in chapter 7. But, even more, he was an insightful and creative leader and administrator. Among other things, he devised the first sensible system for the transfer of power from one emperor to the next. Despite its theoretical virtues, however, the system broke down just over a year after the first transfer occurred, and Constantine himself played a definitive role in that collapse, leading to his own assumption of imperial power in a reign that was second only to that of the great Caesar Augustus himself in both length and historical consequence.
From the time of Augustus, the first of the Roman emperors, the major political problem at the pinnacle of power had always been the succession. Once an emperor died, who was to succeed him? Augustus himself—unlike many of those who came in his wake—certainly had plans, and they always involved heirs who actually shared his bloodline. But one by one these potential successors died—or, if we believe the rumors, were assassinated—until virtually the last man standing was Augustus’s stepson Tiberius. As emperor, Tiberius too had no legitimate heirs to the throne, and so the world inherited Gaius, otherwise known as the infamous Caligula. The succession went from there, not always happily.
Diocletian decided that there had to be a better way. He himself reigned with an iron fist for nearly a decade before carrying out his design. He devised a system of succession based not on dynastic ties but on merit. It was a plan to keep the empire completely unified, but ruled through a college of four emperors, an administrative unit known as the Tetrarchy (“rule of four”). There would be two senior emperors, each labeled an Augustus. Beneath each of them would be a junior emperor called a Caesar. The Caesars would be chosen based on their experience and qualifications. They would not be blood relatives of the Augusti.
And so it happened. Diocletian became the senior emperor of the East, with a military man named Galerius as Caesar; another military officer, Maximian, became senior emperor of the West, with Constantius—the father of Constantine—as his Caesar. Even though each emperor had principal responsibility for a distinct set of provinces, the empire was not technically divided into four units. Instead, the four were construed as co-rulers of a unified empire. The decisions of one were affirmed by the four; the conquests and victories of one were credited to the others. There were four emperors, but the empire was one.
Most important was the rule of succession that Diocletian devised. When an Augustus died or abdicated, his Caesar would then “move up” and assume his vacated position, and a new Caesar would be chosen by the most senior of the two Augusti.6 This new junior emperor would not be the natural son of the newly elevated Augustus but a figure uniquely qualified for the position. And so, in theory, the system could continue indefinitely, since successors would always be chosen—well in advance—for their abilities to perform the tasks of office, not because of the accidents of birth. It was a completely novel and rather ingenious conception.
It was also doomed to failure. The children of current rulers could hardly be expected to accept the new system passively, and they didn’t.
Because of health issues, after a long and successful reign of over two decades, Diocletian decided to retire from office on May 1, 305. For the sake of a smooth succession, he compelled his rather unwilling co-Augustus, Maximian, to do the same, to make way for the two Caesars, Galerius and Constantius, to rise to the senior offices. For their replacements, according to the principles that Diocletian had devised, two Caesars were chosen as junior emperors: Maximin Daia (not to be confused with the outgoing Augustus Maximian) to serve with Galerius in the East, and Severus to serve with Constantius in the West. There was now a “Second Tetrarchy.”
At the time it may have seemed like a smooth and unproblematic transition, and in a sense it was—until one of the new Augusti died. Then the plan of succession based on qualifications ran afoul of both the dynastic principle and the army.
The background to the story involves the new Augustus of the West, Constantius, and his son Constantine.7 Constantine had risen through the ranks of military and political service over the years, as was natural for a scion of such a high-ranking official. He had served as a junior military officer in the court of Diocletian and then, for a brief time, under Galerius. When Galerius was promoted to be the new Augustus of the East, he realized the potential problem with Constantine, who could well expect an appointment to the level of Caesar in accordance with the traditional dynastic principle. But Constantine was not named to the position and almost certainly harbored some resentment and, possibly, some hope of remedy. If later reports are to be believed, Galerius’s solution to this potential problem was to remove Constantine from the scene by regularly putting him in harm’s way during various military endeavors. One later account, probably apocryphal, claims that Galerius, for his own amusement, once assigned Constantine to fight a lion one-on-one.
Constantine emerged from these attempts unscathed. Soon after Constantius was elevated to the level of Augustus, he requested his son’s transfer to his own service. Whether out of relief or in a moment of weakness, Galerius ceded to the request. In later propaganda we are told that Constantine fled as quickly as he could—before Galerius could change his mind—and, taking the fastest and only state-sponsored imperial route on horseback, hamstrung the horses left behind at each way station to prevent Galerius from fetching him back on second thought.
Constantine, in any event, made it to Gaul, where his father was stationed, and joined him in his military campaigns on the borders, accompanying him to Britain to beat back incursions coming across Hadrian’s Wall. It was there that Constantius took ill and died on July 25, 306.
That is when the dominoes began to fall. In designating his successor in the Tetrarchy, Constantius did not choose one of his great military commanders based on personal merit but instead selected his son Constantine—returning precisely to the rule of dynastic succession that Diocletian had wanted to avoid. The problem is that Maximian, the rather reluctantly retired Augustus of the East, also had an adult son, named Maxentius, who had, along with Constantine, felt slighted by being bypassed for a place in the imperial college at his father’s abdication. Once Maxentius saw that Constantine’s army had invoked the dynastic principle by acclaiming him ruler, he pushed to receive the same privilege. With his urging, the Praetorian Guard in the city of Rome proclaimed him emperor. He assumed control of Rome and Italy, and now the “Rule of Four” had become five. To complicate matters further, Maxentius brought his father Maximian out of retirement to assist him, so that now the five were six. But not for long.
The emperors Galerius, Severus, and Constantine all—rightly—considered Maxentius a usurper, and knew they needed to dispose of him. There was no choice but civil war. It was not easy or swift. Galerius, the senior of the two Augusti, directed Severus to take his army into Italy and, if necessary, lay siege to Rome. Severus did so, but many of his soldiers defected to the opposing side and he was soundly defeated in battle, personally captured, and soon thereafter forced to commit suicide.8 Galerius then decided to take matters into his own hands and attacked Maxentius from the East. He too failed to complete the mission. Finding himself unable to enforce a viable siege on the city, and experiencing numerous defections of troops, he fled Rome and barely managed to escape alive.9
During all this time, Constantine stayed away from the fray, conducting campaigns on his northern border against barbarian threats and allowing the other leaders of the empire to fight it out among themselves. He proceeded to do nothing about the situation for six years. Over that time he learned of problems that Maxentius was experiencing in Rome—famine and food shortages resulting in riots; rampaging soldiers; unjust imprisonments and executions—and reports of Maxentius’s own profligate activities. In 312 CE he decided the time was right. In retrospect he claimed he simply could no longer allow tyranny in the capital. What he did not point out in public was that overthrowing the alleged tyrant would give him possession of Rome, all of Italy, and North Africa.
What especially matters for our narrative here is that, in addition to the enormous political and military consequences of a Constantinian victory, there was a highly unexpected religious outcome. This was to prove even more significant for the subsequent history of the Roman world. It was during his march on Rome, Constantine claimed later, that he experienced his conversion to Christianity.
The march itself was a thing of military beauty. Constantine demonstrated his enormous military prowess, acting boldly and swiftly, accompanying his army over the Alps and destroying all resistance en route. After several victories over Maxentius’s forces in northern Italy, along with the surrender of other strongholds that could see the writing on the wall, Constantine moved his army south within striking distance of Rome itself, in preparation for an ultimate battle with the usurper, after which he would take control of the entire Italian peninsula. That is when Constantine had a vision.
At least, that is when Constantine later claimed he had his vision. One of the thorniest issues that biographers of Constantine contend with is the question of his vision—or, rather, his visions. As it turns out, we have several contemporary reports of several visions, all of them recorded by writers who personally knew Constantine and appear to be relating what they heard from him and/or his companions directly. As a result, it is very hard to know whether Constantine had one vision or two or three, whether the vision or visions came while he was awake or asleep, whether they came while he was still campaigning in Gaul, or en route to Rome, or stationed just north of Rome on the night before his battle.
To make sense of the reports that have come down to us, we have to put them in the context of Constantine’s personal religious life, and that will require some further background.
We have comparatively excellent sources for Constantine’s adult life, including his own writings, laws he enacted, a biography written about him by the fourth-century Christian bishop of Caesarea Maritima and “father of church history” Eusebius, and other contemporary reports.10 But we are handicapped when it comes to his life prior to his accession to the throne, including his religious life. For this we have very slim records. We do know he was born in the northern Balkans, and we can assume that he originally participated in local indigenous religions that would have included such deities as the Thracian rider gods, divine beings astride horses. As was true of all citizens in the empire, he would also have participated in civic religious festivals, including the cults worshiping deceased Roman emperors. The Roman army too had its deities of choice; as a soldier and then commander Constantine would have worshiped these as well.11
What we do not know is how well informed he was of Christianity in the years before his conversion. His mother, Helena, was later in life—well into Constantine’s reign—a very committed Christian, and some have suspected that she had Christian leanings even in his youth. But we simply have no compelling evidence. We have a bit more information about his father, Constantius, and some observers have claimed him too for the Christian cause, none more famously than Constantine’s biographer, the Christian Eusebius.12 It is indeed worth noting that during the original Tetrarchy, when Diocletian declared an empire-wide persecution (see chapter 7), Constantius paid the policy little more than lip service, shutting down some churches but not arresting, torturing, or martyring any Christians. Was he a sympathizer or even a devotee himself? Some historians have also been struck by the fact that one of Constantius’s daughters (with a later wife) was called Anastasia, a Greek name that means resurrection—a highly appropriate name had her father been a Christian.
It is not likely, however, that he was. More plausibly Constantius, like the emperor Aurelian some years earlier, was a “henotheist,” revering one god as superior to all others without denying the divinity of the others. In particular, he may have worshiped above all else the god of the sun, Sol Invictus (“Unconquered Sun”). That would make sense both of the fact that Constantine himself remained a pagan prior to his march on Rome in 312 CE and of Constantine’s later ruminations about what led him to the god of the Christians.
We have three principal sources of information for the vision(s) of Constantine that led to his conversion. The first comes to us in a flattering speech—known as a panegyric—delivered by an anonymous orator in 310 CE, before Constantine had initiated his final actions against Maxentius. The speech was occasioned by a military victory in a skirmish with Maximian, Maxentius’s father, who had been brought out of retirement. As was always the case with panegyrics, the speaker himself wrote his address and made it entirely sycophantic. Such speeches were designed to praise the recipient as one of the greatest human beings the universe had ever seen, as revealed by the subject’s activities and experiences. It was in the context of celebrating Constantine’s marvelous character that the panegyrist of 310 CE described a vision the emperor had recently had of the god Apollo, who is often associated in ancient thought with the sun and considered, then, the sun god.13
In the speech we are told that, after winning his battle, Constantine decided to visit a magnificent temple of Apollo, probably at Grand, Vosges (northeastern Gaul, modern France). There, outside the temple, Constantine had a vision of the god himself, who offered him several laurel wreaths, each of which symbolically represented thirty years of life, thus indicating that Constantine would be allotted a preternaturally long mortal existence. More than that, the god indicated that Constantine was the one who would rule the entire world. The panegyrist did not stop there, however. He went on to indicate that Constantine was a kind of human manifestation of Apollo himself: among other things, like the god he was young, handsome, and a bringer of health.
If any such vision did occur—or if Constantine thought it occurred, or even simply said it did—this may well be the time at which he began to revere Sol Invictus. Possibly he became a henotheist. This would not have required him to stop being pagan, as we will see more fully in chapter 3. He still could have acknowledged the divinity of other gods and recognized the right and even obligation of other people to worship them. But he may have turned his own entire focus onto the god he considered to be above all gods, choosing—as the emperor who aspired to be the greatest and most powerful human on earth—to worship only the greatest and most powerful divinity in heaven.
The fullest version of Constantine’s vision, or visions, appears in a record produced nearly three decades later. It is also the most important source for Constantine’s conversion. The report appears in the Life of Constantine, a biography of the emperor by Eusebius, who had firsthand information from the emperor himself and claims that his account of Constantine’s conversion was what the emperor himself revealed and swore to be true.14
Eusebius indicates that Constantine decided, for the good of the empire, to overthrow the tyrant of Rome, Maxentius. He knew that he would need divine help in his endeavor. To the regret of many a later historian, Eusebius does not tell us when exactly Constantine’s appeal for heavenly assistance occurred; all he says is that it was “on a military campaign he was conducting somewhere.” Whenever it was, it happened before Constantine engaged Maxentius in the final battle for Rome. Constantine reflected on his religious options and realized that, without help from above, his cause could not be won:
Knowing well that he would need more powerful aid than an army could supply because of the mischievous magical devices practiced by the tyrant, he sought a god to aid him. He regarded the resources of soldiers and military numbers as secondary, for he thought that without the aid of a god these could achieve nothing, and he said that what comes from a god’s assistance is irresistible and invincible. He therefore considered what kind of god he should adopt to aid him (Life 1.27).
Clearly Constantine was still at this stage operating within a pagan context, trying to decide where to appeal for divine help. As he reflected he came to regard a polytheistic position as politically and militarily untenable, for a remarkably empirical reason. All of his predecessors on the throne had “attached their personal hopes to many gods” and so worshiped them in expectation of success. But all failed miserably and “met an unwelcome end.” (This of course was not true, but it is how Eusebius quotes the process of Constantine’s thought.) The one exception was his father, Constantius, who died peaceably after having turned to the worship of only one god: “Only his own father had taken the opposite course to theirs by condemning their error, while he himself had throughout his life honored the God who transcends the universe, and found him a Savior and guardian of his Empire and a provider of everything good” (Life 1.27).
Constantine—or more likely Eusebius himself—was now claiming that Constantius was not just a henotheist but a worshiper of the Christian god. The historical record suggests otherwise, but at this stage we are more interested in Constantine’s thought process, at least as it is laid out in Eusebius’s account. Constantine went on to realize that the two previous rulers who had attacked Maxentius—Severus and Galerius—“had assembled their forces with a multitude of gods and had come to a dismal end.” Clearly the polytheistic option was not working in the battle for Rome. And so Constantine came to a decision, concluding “that it was folly to go on with the vanity of the gods which do not exist, and to persist in error in the face of so much evidence, and he decided he should venerate his father’s God alone” (Life, 1.27).
Constantine turned to this one god in prayer, and he was rewarded with a vision. And not just he alone: he and his entire army.
About the time of the midday sun, when day was just turning, he said he saw with his own eyes, up in the sky and resting over the sun, a cross-shaped trophy formed from light, and a text attached to it that said, “By this conquer.” He and the whole company of soldiers that was then accompanying him witnessed the miracle and were gripped by amazement (Life 1.28).
Constantine could not understand the meaning of the vision, and he pondered the matter until nightfall. Then, in a dream, Christ appeared to him with the same sign Constantine had seen in the sky, directing him to make a copy of it as protection from the attacks of his enemies.
Constantine apparently did not fathom what it was he had seen in either experience. In his confusion he summoned several religion experts for an explanation. This is the clearest evidence that Constantine was not, at this point, desiring to become a Christian. He evidently did not fully realize who the Christian god was or what he stood for. He needed instruction. His advisors explained who Christ was as the “only begotten Son of the one and only God,” who could bring “victory over death.” They told him that the sign of the cross was a “token of immortality.” They proceeded to explain why Christ had come to earth and to unfold for him the meaning of the incarnation. Constantine marveled as he listened—indicating, yet again, that it was news to him—and decided to explore “the divinely inspired writings” for himself. He did so, and with the help of his advisors “deemed it right to honor the God who had appeared to him” by worshiping him alone. Constantine then summoned his goldsmiths and jewelers and explained that he wanted a physical representation of the sign he had seen in his vision and dream, and they made it for him.
At this point in his account, Eusebius injects a personal note, claiming that after the emperor had described to him the object, he brought it out to show him.15 It was a tall pole plated with gold, with a crossbeam that gave it the shape of a cross. At the very top was a jeweled and gilded wreath on which were superimposed the two Greek letters chi and rho—which are the first two letters of the Greek word for “Christ.” Below the crossbeam was a suspended cloth. Eusebius indicates that “this saving sign was always used by the Emperor for protection against every opposing and hostile force, and he commanded replicas of it to lead all his armies” (Life 1. 31). In other words, Constantine took this object—known as the labarum—into battle with him, and it ensured victory. It apparently worked every time.
We also have a third account of Constantine’s conversion, which is, to say the least, difficult to reconcile with the previous two. This other version comes to us in the writings of a Christian historian and theologian named Lactantius. Lactantius is a particularly important source of information. For one thing, he was personally acquainted with Constantine: in fact, he was appointed by the emperor to be the personal tutor of his eldest son Crispus. For another thing, his account was written not decades later (as was the case with Eusebius) but just a few years after the event. Is it the same event? Most historians have thought so, even though the differences are striking.
The account appears in a small book—a pamphlet, really—that is particularly notable for its unabashed Schadenfreude, called Deaths of the Persecutors. In this work Lactantius recounts with barely disguised glee the horrible and excruciating deaths experienced by the Roman officials responsible for the persecutions of the Christians. The book comprises not merely grisly deathbed scenes, however, but also a good deal of other historical information. Chapter 44 gives an account of Constantine’s conversion that is terse and direct. According to this version, the epiphany came to Constantine the night before the decisive battle with Maxentius for the control of Rome. In a dream Constantine was instructed—we are not told by whom—to place the “heavenly sign of God” on the shields of his soldiers before going into battle. The next day he did so, instructing the soldiers to have their shields decorated with a letter X crossed through the middle by the letter I, the top of which was to be rounded. This (here is a parallel with Eusebius) would have looked then like a Chi-Rho (the letter chi looks like an X and the rho looks like a capital P—i.e., a straight I with the top rounded). Armed with these shields, Constantine’s troops went into battle and, as it turns out, routed the opposition.
Various scholars have suggested different ways of reconciling the different versions of Constantine’s vision or visions. Some think he had just one vision, two years before the Battle at the Milvian Bridge (just before the panegyric of 310 CE), which at the time he took to be of Sol Invictus but later came to interpret as being instead a vision of Christ. In this view, at a still later date Constantine came to think he had always understood it to be Christ and that, since the vision was so closely connected with his ultimate victory, he came to “remember” that it occurred the night before the battle. At the other extreme of interpretation, some have argued that Constantine was simply a visionary who had lots of visions and dreams, sometimes muddling them all up. It is striking that Eusebius himself, in a speech praising Constantine near the end of his life, indicates that Constantine was a famous visionary and that he had “thousands” of visions along with “thousands” of dreams in which Christ appeared to him.16
The accounts do share some striking features. For one thing, in each case the vision involved a solitary god whom Constantine decided was the only one to be worshiped: he chose no longer to engage in polytheistic practices. Moreover, the account from the panegyrist in 310 and, more striking still, the account of Eusebius many years later both agree that Constantine did not become a Christian immediately after the dream. The panegyrist says nothing about him becoming a Christian at all, which may suggest the conversion had not happened yet, or that Constantine had not yet made it public, or that the pagan orator decided not to delve into that little detail. Eusebius admits that the emperor needed to do considerable consultation, reading, and reflecting before working out the implications of what he saw. Who knows how long that would have taken?
One reason we have difficulty working out what the vision or dream was and when exactly it occurred is that modern research on conversion has demonstrated that, long after such an experience, a convert tends to confuse what actually happened in light of everything that occurs in its aftermath.17 That is to say, years later, the accounts people tell, to both themselves and others, have been slanted by all they have learned, thought, and experienced in the interim. Surely that was true of Constantine as well.
No one will ever solve the problem of what actually happened, or when, to the satisfaction of all interested parties.18 But here is one plausible reconstruction. Whether actual or imagined, the vision experience contributed to Constantine’s religious meditations as he was reflecting on the problem of the gods and how to find much-needed divine support for his assault on Maxentius. He became convinced that his vision was a sign from the one true and ultimate god, and he decided to worship him.
My best guess is that the vision occurred just before it was first reported, in 310 CE, and at that point Constantine became a henotheist, one who revered the sun god, Sol Invictus, above and in lieu of all others. This would be two years before he launched his assault on Maxentius, and in that time he had plenty of opportunities to reflect on his new religious commitments. Among other things, he became increasingly cognizant of the growing Christian movement. (In chapter 6 we will be discussing just how rapidly it was growing at the time.) Soon before the battle for Rome, he had another vision, or a dream, or both, and came to a decision. This decision was not that he would switch loyalties from Sol Invictus to the god of the Christians. Instead, he decided that Sol Invictus was the god of the Christians.19
Constantine became a Christian convert. Possibly the most important point to make about the conversion is that Constantine—as is true of all converts—did not and could not understand everything there was to know about the Christian faith at the time. His faith and his knowledge may have been very rudimentary indeed. He may not have known that he needed to be baptized at some point. He may not have known that Christians not only refused to worship other gods but believed the pagan gods were demons and not gods at all. He may not have known that there were ethical requirements that went along with being Christian. He may not have known that there were refined theological views and serious debates among the Christians about the nature of God, the identity of Christ, and the relationship of Christ and God. He may not have known lots of things.
What he apparently did know was that he wanted to worship the Christian god and that god only. He went into battle with that conviction. And he emerged victorious.
The battle itself reads almost as an anticlimax to the story and is quickly told. In the wake of the failed attempts by both Severus and Galerius, one can see why Constantine would be anxious about the campaign. But he had several advantages his predecessors lacked, and Maxentius, in this instance, made a disastrous decision. Constantine was aided by the fact that Maxentius’s father, Maximian, a brilliant military commander, was no longer part of the equation: he had committed suicide under duress (from Constantine) two years earlier. Even more, Maxentius’s situation in Rome had grown dire. When he had started his reign, the city had welcomed him with open arms. But the problems mentioned above had taken their toll.
In anticipation of the assault from the north, Maxentius made one rather sensible move. He destroyed all the bridges that crossed the Tiber River. That would make engagement more difficult for an attacking army. But then, almost as an afterthought, he made a second decision that was disastrous. He chose not to steel the city against a coming siege but to come out in force and face the opposition in the field.
With the bridges out, however, there was no way to cross the Tiber heading north onto favorable battlegrounds. So Maxentius had a temporary pontoon bridge built next to the recently destroyed Milvian Bridge, and he and his army crossed it. With their backs up against the river and soon outmaneuvered, they were routed. Troops desperately tried to recross the pontoons in a beeline for the city, but under the crushing weight, the bridge collapsed. Many of the soldiers, and Maxentius himself, drowned in the Tiber.20
Constantine entered Rome the next day as its new ruler and the emperor of the entire western half of the empire. As we will see in chapter 8, it was another twelve years before he became sole ruler of the empire as a whole. But he was very good at biding his time. In the meanwhile he came to see the wisdom of his religious decision. He had committed his life and worship to the god of the Christians and then he had won his victory. The Christian god was greater than the other gods of Rome. He alone would be Constantine’s god. Constantine had become a Christian.
Or had he?
For long (and somewhat dreary) years scholars debated the sincerity of Constantine’s conversion. Many experts today regard the debate as a wasted effort, even if more casual observers continue to consider it a live question. The debate started in 1853 with a Swiss scholar named Jacob Burckhardt, who argued in his book Die Zeit Konstantins des Grossen (The Age of Constantine the Great) that Constantine was ultimately driven not by religious zeal but by a “consuming lust for power.” There is a lot that can be said for this argument in and of itself, but in addition Burckhart drew a corollary: Constantine recognized that the burgeoning Christian church could assist him in reaching his megalomaniacal goals, and so he forged an alliance with it out of personal ambition. Constantine in fact could not have cared less about the church and its truth claims.
Over the course of the debate, historians cited numerous pieces of evidence in support of this basic thesis. To begin with, Constantine continued to embrace pagan views in the public eye. No medium in Roman antiquity better propagandized an emperor’s personal agenda than the issuance of coins. The imperial mints selected imagery and inscriptions that would embody the views, ideologies, and imaginations of the ultimate ruler. With that in mind, it is no doubt significant that, beginning in 310, Constantine’s coins began to show images of Sol Invictus, the sun god. As we have seen, one can plausibly date his professed henotheism to that time. Yet more striking for those who have wanted to argue against the sincerity of his Christian conversion: this imagery continued for years after the battle at the Milvian Bridge. If Constantine had genuinely become Christian, why did he keep issuing coins with pagan imagery?
Moreover, it was argued, after his alleged conversion, Constantine and those closely connected to him were highly circumspect in their references to God. A case in point is the Arch of Constantine still preserved today near the Colosseum in Rome. This was the triumphal arch the senate had constructed to celebrate Constantine’s great victory over Maxentius, dedicated on Constantine’s second visit to Rome in 315 CE. On the arch is an inscription describing the great event, including the divine assistance that Constantine had invoked going into battle. Yet there is no explicit reference to the Christian god. On the contrary, the inscription refers in rather bland and noncommittal terms to guidance provided by the “inspiration of divinity.” If Constantine had been a true convert, would he be reluctant to declare outright that it was specifically the Christian god who had helped him?
Moreover, advocates for Constantine’s insincerity pointed out that, well after the decisive battle for Rome, Constantine certainly did not act like a Christian. Soon after his victory Constantine ordered the execution of his ten-year-old nephew, son of Galerius. Would a Christian kill a ten-year-old child? Later in his career he ordered the execution of his own eldest son, Crispus, who was next in line to succeed him, and then his own wife, Fausta. These seem to be actions not of a true believer but of a despot. Finally, it was noted that Constantine refused to be baptized as a Christian until on his deathbed, some twenty-five years after his supposed conversion. Was it then that he finally “saw the light”?
For all these reasons, scholars of the late nineteenth and twentieth centuries disputed whether Constantine was actually committed to the Christian cause. Historians today, however, tend to read the evidence differently.
It is absolutely true that Constantine continued to use the imagery of Sol Invictus in his personal propaganda after the events of 312 CE, sometimes even having himself portrayed alongside the sun god in twin profile. That is not evidence that he worshiped divinities other than the Christian god, however. Christians before Constantine’s day had sometimes identified the Christian god as the god of the sun, and as I argued earlier, Constantine appears not to have chosen the god of the Christians over Sol Invictus but rather to have identified him with Sol Invictus.
The fact that Constantine did not always identify his god as the god of the Christians—for example, on the triumphal arch in Rome or on his coins—could well be for other reasons. For one thing it needs to be emphasized that Constantine himself did not write the inscription that appeared on the arch. This was a monument made for him, not by him.
Even more important, Constantine himself may have had solid reasons not to want to flaunt his new religious commitment. As one modern Constantine scholar, Harold Drake, has argued, Constantine was self-consciously a ruler not only of Christians but of all people in his empire, Christian, pagan, and Jew alike. As such he chose to affirm his monotheistic faith without offending the sensitivities of any of his constituencies. Constantine was far too politic to make a public display of his distinctive Christian beliefs. At the same time he was unwilling to compromise his monotheistic commitments. In order to balance and accommodate both competing agendas, imperial and Christian, Constantine tactfully chose public language that could embody his commitments without alienating those who held other views.21
As for Constantine not always acting as a Christian and doing things that Christian ethicists strongly insist one should not do, we need always to remember that his conversion was not an instantaneous adoption of traditional Christian beliefs and practices—or ethics. Moreover, historians must resist the urge to define “Christian” according to certain preconceived notions and then judge Constantine accordingly. Are we to imagine that someone is not a Christian if they behave badly? It is true, some of Constantine’s actions were highly transgressive of traditional Christian morality. On the other hand, he did have an empire to run. He would not have lasted a month if he had styled his rule on the Sermon on the Mount.
What about Constantine’s decision to delay baptism until the last minute? This is probably the least convincing of the arguments, since it was not an unusual practice. This was especially true among Christians who took seriously theological claims that sins committed after baptism could not be forgiven but would lead to eternal punishment. We see such claims already in the New Testament: “For if we willingly sin after receiving the knowledge of the truth, there is no longer left to us a sacrifice for sins but a fearful expectation of judgment and a furious fire that will consume the enemies” (Hebrews 10:26–27; see also Hebrews 6:4–6). Anyone who believed this can hardly be excused for delaying baptism until the very end. Many did so.
There is in fact overwhelming and public evidence that Constantine was a very real Christian during his reign, even if he only gradually came to understand fully what that meant. Some of the most striking policies he enacted after his victory at the Milvian Bridge involved favors poured out on the Christian churches. Within months of assuming control of Rome he came to an agreement with his co-emperor Licinius, now ruling the East with the passing in 311 of Galerius, that brought a complete cessation of the persecution begun ten years earlier under Diocletian. This so-called Edict of Milan (which was not an edict and was not from Milan) gave complete freedom of religious expression to all inhabitants of the empire, ending once and for all the prosecution of Christians.22
Christianity, however, was not only decriminalized; it went from being a persecuted faith to being the religion of most-favored status. Constantine commissioned and financed the building of numerous Christian churches both in Rome and abroad, most notably the Lateran Basilica, which was to play such an instrumental role in the history of Christianity as the official cathedral of the Roman bishop (i.e., the pope). He showered beneficences on Christian clergy. He instructed the leading administrator of Africa to restore all the property that had been confiscated from the Christian churches during the persecutions.
One might argue that Constantine was simply siding with the church for reasons of his own without being personally committed to Christian truth claims. In theory that could be so, but it is completely discredited by two other kinds of evidence: the first is Constantine’s almost immediate involvement with Christian practical and theological disputes, and the second are words that issued from his own pen in which he spelled out with clarity his religious views.
In terms of his active participation in church affairs, already in 313 and then more vigorously in 314 Constantine inserted himself into the rancorous Donatist controversy of Northern Africa. This was an intense debate over what should be considered the legitimate Christian church community and who should be considered its legitimately appointed leaders. Constantine threw himself into the fray not particularly caring at first which side was right, but over time he came to a very clear opinion on the matter, siding (to no one’s great surprise) with the view supported by the great majority of church leaders, especially those in Rome.23
Yet more striking was the Arian controversy, which came to a head some thirteen years later. Now the issues did not involve church polity but hard-core theology, specifically the hot and detailed question of the identity of Christ and his relationship with God the Father (Are they equal? Or is the Father greater? Are they co-eternal? Or did the Father exist first?). Constantine, like most Christians to this day, did not follow, or even much appreciate, all the nuances of the debate. But he was deeply invested in it and called the famous Council of Nicaea in 325 CE in order to resolve it. He not only called the council; he actively participated in the discussions and enforced the final decision. It is a remarkable moment of history. Here was a hardened, experienced, and seriously bloodied military commander and iron-fisted ruler of the Roman state debating the philosophical meaning of words of Scripture with Christian bishops. It is hard to say he was not committed to the cause.
Above all we have words that Constantine wrote and publicly spoke, which show beyond any doubt his deep Christian sensibilities. Nowhere can this be seen more clearly than in his address widely known as the Oration to the Saints.24 In written form the speech spans twenty-six chapters. It would have taken two hours to deliver orally. We know it was given around the time of Easter, but we don’t know which year, with scholars proposing dates ranging from 315 to (somewhat more plausibly) 325 CE. The speech is principally a defense of the Christian belief over the views of paganism. It expresses Constantine’s philosophical and theological views, even though no theologian then or now would consider it overwhelmingly deep or perspicacious. Constantine was highly educated, but he was no professional thinker. Still, the speech gives us his religious perspectives and shows clearly how deeply he felt committed to them—and how closely they aligned with his political objectives. It is always important to remember the point made at the beginning of this chapter. Ancient people, whether pagans, Jews, or Christians, did not neatly differentiate between the religious and the political. They would have had a hard time understanding the difference.
There certainly is not a clear difference in this speech. Early on, Constantine makes an impassioned plea that there is and must be only one ultimate divine ruler, one god over all. If there were many divinities, then people would commit a sacrilege anytime they chose to worship any one of them. But, even more significant, if there were many divine rulers, there would be divisiveness rather than unity. What the world needs is unity. Constantine is quite openly not thinking only of the unity of heaven. He is equally, if not more, concerned about life on earth.
The divine situation, then, reflects the human. Numerous divinities all vying for attention would create division, envy, and jealousy. This, in his words, “would mar the harmonious concord of the whole, as many disposed in different ways of the shares allotted to each, and took no thought to maintain the whole world in the same state and according to the same principles.” Such a state of affairs would lead to the “confusing of all things.” And by “all” Constantine really means all. “The constellations would be in disarray, the seasons could not change in consistent patterns, the fruits of the earth could not grow, day and night would be confused.” There has to be one ruler over all. The implication, should anyone miss it, is that there needs to be one emperor over all as well.
That does not mean that Constantine’s speech is simply a power grab. It means that his religious commitment to worship the one God of heaven affected his sense that he himself was to be the one ruler on earth. As such he was completely committed to the Lord of all. His allegiance was completely Christian, as he himself declares in the oration: “My proper task is to hymn Christ through my way of life and the thanksgiving due to him from us in return for many great benefits” (Oration, 5).
Constantine was decidedly in favor of the “many great benefits” that were his through the worship of the Christian god. That may not sound like a disinterested view of theology or worship. But in an ancient context it is the least extraordinary thing about his deeply held commitment.
Some historians have argued that if Constantine were really a Christian, he would have worked harder to convert his pagan subjects. That he clearly did not do. As Harold Drake has shown, however, this is no argument against his commitment to the Christian cause. It is evidence of the kind of Christian Constantine was and wanted to be. There were many, many Christians of his day—just as there have been many, many Christians in all the centuries that followed—who did not find it incumbent upon themselves to foist their Christian views on those who adhered to other religious traditions.25 He had seen with perfect clarity the failure of forceful governmental intervention in religion, and he wanted no part of it. He was happy to support the Christians, to promote monotheistic piety of various kinds, and to allow people to worship God or the gods as they saw fit.
His conversion had serious repercussions. All the emperors of Rome from that time on—with one brief but notable exception—were Christian. Christianity was to take over the Roman world, becoming the official religion of the empire and eventually the dominant religion of the West.