Constantine the Great to 323 CE: ‘I Myself Was the Instrument’

Statue of Constantine the Great in Yorkminster / Creative Commons

Even had its Empire never existed, Byzantium would surely have impressed itself upon our minds and memories by the music of its name alone.

By Dr. John Julius Norwich
Ancient Historian

With such impiety pervading the human race, and the State threatened with destruction, what relief did God devise? … I myself was the instrument he chose . . . Thus, beginning at the remote Ocean of Britain, where the sun sinks beneath the horizon in obedience to the law of Nature, with God’s help I banished and eliminated every form of evil then prevailing, in the hope that the human race, enlightened through me, might be recalled to a proper observance of God’s holy laws.

Constantine the Great, quoted by Eusebius, De Vita Constantini, II, 28

In the beginning was the word – surely one of the most magically resonant place-names in all history. Even had its Empire never existed, even had there been no W. B. Yeats to celebrate it, even had it remained what it was at the outset – a modest Greek settlement at the furthest extremity of the European continent, without pretensions or ambitions – Byzantium would surely have impressed itself upon our minds and memories by the music of its name alone, conjuring up those same visions that it evokes today: visions of gold and malachite and porphyry, of stately and solemn ceremonial, of brocades heavy with rubies and emeralds, of sumptuous mosaics dimly glowing through halls cloudy with incense. Historians used to maintain that the town was founded in 658 BC by a certain Byzas, leader of a group of colonists from the Greek city of Megara. They now inform us that Byzas may never have existed, and we can only pray that they are right. Magic is always best left unexplained.

The Eastern (Byzantine) and Western Roman Empires at the time of Constantine’s fight with Licinius / Creative Commons

Next, the site; and this too was supreme. Standing on the very threshold of Asia and occupying the easternmost tip of a broad, triangular promontory, its south side washed by the Propontis – which we nowadays call the Sea of Marmara – and its north-east by that broad, deep and navigable inlet, some five miles long, known since remotest antiquity as the Golden Horn, it had been moulded by nature at once into a magnificent harbour and a well-nigh impregnable stronghold, needing as it did major fortification only on its landward side. Even an attack from the sea was difficult enough, the Marmara itself being protected by two long and narrow straits – the Bosphorus to the east and the Hellespont (or Dardanelles) to the west. So perfectly suited, in fact, was the place for colonization that the inhabitants of Chalcedon, who had founded their own town seventeen years earlier on the opposite shore of the Bosphorus, became proverbial for their blindness: how otherwise, it was said, could they possibly have missed so infinitely preferable a site only a mile or two away?

Finally, the man: Constantine I, Emperor of Rome. No ruler in all history – not Alexander nor Alfred, not Charles nor Catherine, not Frederick nor even Gregory – has ever more fully merited his title of ‘the Great’; for within the short space of some fifteen years he took two decisions, either of which alone would have changed the future of the civilized world. The first was to adopt Christianity – the subject, only a generation before, of official persecutions more brutal than any that it has suffered before or since – as the official religion of the Roman Empire. The second was to transfer the capital of that Empire from Rome to the new city which he was building on the site of old Byzantium and which was to be known, for the next sixteen centuries, by his name: the city of Constantine, Constantinople. Together, these two decisions and their consequences have given him a serious claim to be considered

  • excepting only Jesus Christ, the Buddha and the Prophet Mohammed,
    the most influential man in all history; and with him our story begins.

It is all too typical of our fragmentary knowledge of the later Roman Empire that although we can say with confidence that Constantine was born at Naissus in the Roman Province of Dacia – the present Yugoslav town of Nis – on 27 February, we cannot be certain of the year. Traditionally it is given as AD 274, but it could equally well have been a year or two on either side. His father Constantius – nicknamed ‘Chlorus’, the Pale – was, already at the time of his son’s birth, one of the most brilliant and successful generals in the Empire; his mother Helena was not, as the twelfth-century historian Geoffrey of Monmouth would have us believe, the daughter of Coel, mythical founder of Colchester and the Old King Cole of the nursery rhyme, but a humble innkeeper’s daughter from Bithynia. Some historians have questioned whether she and Constantius were ever actually married; others, pagan and therefore hostile to the family, have gone further still and suggested that as a girl she had been one of the supplementary amenities of her father’s establishment, regularly available to his clients at a small extra charge. Only later in her life, when her son had acceded to the supreme power, did she become the most venerated woman in the Empire; only in 327, when she was already over seventy, did this passionately enthusiastic Christian convert make her celebrated pilgrimage to the Holy Land, there miraculously to unearth the True Cross and so gain an honoured place in the Calendar of Saints.

Laureate head of Diocletian / Photo by G.dallorto, Istanbul Museum of Archaeology, Wikimedia Commons

Whatever the year of his birth, Constantine can still have been little more than a child when his father became one of the four rulers of the Roman Empire. As early as 286 the Emperor Diocletian, having reached the conclusion that the Empire had grown too unwieldy, its enemies too widespread and its lines of communication too long to be properly governable by any single monarch, had raised an old comrade-in-arms named Maximian to share his throne. He himself, who had always taken more interest in his eastern dominions, had based himself at Nicomedia (the modern Izmit) on the Sea of Marmara, roughly equidistant from the Danube and the Euphrates; under his patronage it had grown in size and magnificence until it bore comparison with Antioch, Alexandria – even with Rome itself. But Rome, by Diocletian’s day, had little to sustain it but the memory of past glories; its geographical position alone disqualified it from serving as an effective capital for the third-century Empire. When Maximian assumed the throne of the West, it was understood from the outset that he would be ruling principally from Mediolanum, more familiar to us as Milan.

Two Emperors were better than one; before long, however, Diocletian decided to split the imperial power still further by appointing two ‘Caesars’ – generals who, while remaining junior to himself and Maximian (to whom he had given the title of ‘Augusti’), would also exercise supreme authority in their allotted territories and would ultimately inherit the supreme positions in their turn. One of these first Caesars, a rough, brutal professional soldier from Thrace named Galerius, was given charge of the Balkans; the other, to be based in Gaul but with special responsibility for the reimposition of Roman rule in rebellious Britain, was Constantius Chlorus.

The drawbacks of such an arrangement must have been obvious, even at the time. However much Diocletian might emphasize that the Empire still remained single and undivided, with a single law and structure of command, it was inevitable that he or his successors would sooner or later find themselves with four Empires instead of one, each of them at loggerheads with the rest. And this, as things turned out, is exactly what happened. For some years all went smoothly enough – years which the young Constantine spent at Diocletian’s court, possibly in some degree a hostage to ensure his father’s proper behaviour (for none of the four tetrarchs entirely trusted his colleagues) but also as a prominent member of the imperial entourage.

It was in this capacity that he accompanied the Emperor on his campaign to Egypt in 295-6, passing on his return journey through Caesarea in Palestine – where, we read, he made a lasting impression on a young Christian scholar named Eusebius. In later years this man was to become the local bishop and Constantine’s first biographer: at this time, however, he was still a layman of about thirty, a friend and disciple of Pamphilus, the leading proponent of the Origenist theological school for which Caesarea was famous. As he later reported in his Life of Constantine, his hero

. . . commanded the admiration of all who beheld him by the indications he gave, even then, of imperial greatness. For no one could be compared with him in grace and beauty of form, nor in stature; while in physical strength he so far surpassed his contemporaries as to fill them with terror.[1]

Two years later, we find Constantine as his master’s right-hand man in another campaign against the Persians; and since during those years he seems seldom to have left Diocletian’s side, we must assume that he witnessed, in 303, the deliberate burning of the newly completed cathedral at Nicomedia – the dramatic inauguration of those famous Persecutions that were to rage, scarcely controlled, for the next eight years. But then, in 305, there occurred an event unparalleled in the history of the Roman Empire: the voluntary abdication of the Emperor. After twenty years on the imperial throne, Diocletian had had enough of power; he now withdrew from the world to live in relative obscurity in the vast palace that he had built for himself at Salona (the modern Split) on the Dalmatian coast – forcing an intensely unwilling Maximian to abdicate with him.[2]

Bust of Emperor Constantius I Chlorus / Photo by shakko, Wikimedia Commons

The full – and diabolically complicated – sequence of events that followed this unprecedented step need fortunately not detain us here; suffice it to say that Galerius and Constantius Chlorus – who had by now abandoned Helena to marry Maximian’s adopted stepdaughter Theodora – were proclaimed Augusti as arranged, but that the appointment of their successors, the two new Caesars, was hotly disputed; and that Constantine, finding himself passed over and fearing for his life, fled at night from Galerius’s court at Nicomedia – to avoid pursuit, hamstringing the post-horses behind him as he went – and joined his father at Boulogne. There he found that a Roman army under Constantius’s command was preparing a new expedition to Britain, with the objective of driving the marauding Picts back across Hadrian’s Wall. Father and son crossed the Channel together, and within a few weeks their operation had proved successful. Shortly afterwards, however, on 25 July 306, Constantius Chlorus died at York; and the breath had scarcely left his body before his friend and ally, the charmingly named King Crocus of the Alemanni who was commanding the auxiliary Frankish cavalry, acclaimed Constantine as Augustus in his father’s stead. During the short summer campaign, the young man seems to have earned the genuine admiration and respect of the local legions, who immediately took up the cry. There and then they clasped the imperial purple toga around his shoulders, raised him on their shields and cheered him to the echo.

It was a notable triumph, and one which became greater still as the word spread through Gaul, province after province pledging the young general its loyalty and support. But Constantine still needed official recognition. One of his first actions, therefore, after his proclamation was to send to Galerius at Nicomedia, together with the official notification of his father’s death, a portrait of himself with the attributes of Augustus of the West, and wearing the imperial wreath of bay. Lactantius tells us that Galerius’s instinctive reaction when he received this portrait was to hurl it into the fire; only with difficulty were his advisers able to persuade him of the danger of setting himself up against an infinitely more popular rival. On one point, however, the Emperor remained firm: he refused point-blank to recognize the young rebel -for such, in fact, Constantine unquestionably was – as an Augustus. He was prepared, reluctantly, to acknowledge him as Caesar; but that was all.

For Constantine, it was enough – for the present. Perhaps he did not yet feel ready for the supreme power; at any rate he remained in Gaul and Britain for the next six years, governing those provinces on the whole wisely and well – though he could be capable, when roused, of cruelty and even brutality. (After a rebellion by certain Frankish tribes in 306, thousands were thrown to the wild beasts in the circus – to the point, wrote one contemporary, that the animals themselves became exhausted with so much slaughter.) On the other hand, he vastly improved the condition of slaves and the otherwise oppressed, while his reputation for sobriety and sexual rectitude stood out in dramatic contrast to that of most of his predecessors.

This rectitude did not, however, prevent him from putting aside his first wife, a certain Minervina, in 307 in order to make an infinitely more distinguished alliance – with Fausta, the daughter of the old Emperor Maximian. The latter had by now revoked his involuntary abdication of two years before, had resumed the purple in defiance of Galerius and had made common cause with his son Maxentius; together the two had won over not only the whole of Italy to their cause but, as far as could be ascertained, Spain and North Africa as well. Their position, however, was not yet secure. A concerted attack by Galerius – flinging in his armies from the Danube, quite possibly reinforced by the eastern legions – could still be dangerous for them; and if Constantine were simultaneously to march down against them from Gaul their future would be bleaker still. The marriage was therefore diplomatically advantageous to both sides: for Maximian and Maxentius it meant that they could probably count on Constantine’s alliance if and when they needed it, while the latter for his part could now claim family links with two Emperors instead of one.

How long Constantine would have been content to rule only a relatively remote corner of an Empire that he was determined to make entirely his own, we cannot tell; for, in April 311, a few days after issuing an edict of toleration in favour of the Christians – and so putting an end, in theory at any rate, to the Great Persecution – Galerius, the senior Augustus, died at Sirmium (now Sremska Mitrovica) on the river Sava. Both Eusebius and his fellow-chronicler Lactantius dwell, with a morbid and most un-Christian delight, on the manner of his death:

Suddenly an abscess appeared in his privy parts, then a deep-seated fistular ulcer; these could not be cured and ate their way into the very midst of his entrails. Hence there sprang an innumerable multitude of worms, and a deadly stench was given off, since the entire bulk of his members had, through gluttony, even before the disease, been changed into an excessive quantity of soft fat, which then became putrid and presented an intolerable and most fearful sight to those that came near it. As for the physicians, some of them were wholly unable to endure the exceeding and unearthly stench, and were butchered; others, who could not be of any assistance, since the whole mass had swollen and reached a point where there was no hope of recovery, were put to death without mercy.[3]


[LEFT]: A gold Aureus of the Emperor Licinius / Clemchambers, Wikimedia Commons
[RIGHT]: Bust of Maxentius / Photo by shakko, Wikimedia Commons

The death of Galerius left three men sharing the supreme power: Valerius Licinianus, called Licinius, one of the late Emperor’s old drinking companions whom he had elevated to be his fellow-Augustus three years before and who was now ruling in Illyria, Thrace and the Danube provinces; his nephew Maximin Daia, whom he had named Caesar in 305 and who now took over the eastern part of the Empire; and Constantine himself. But there was a fourth who, though not technically of imperial rank, had long felt himself to be unjustly deprived of his rightful throne: this was Galerius’s son-in-law Maxentius. As the son of the old Emperor Maximian – who had met his end the previous year, by execution or enforced suicide, after an ill-judged attempt in Constantine’s absence to raise the legions against him in southern Gaul -Maxentius had long hated his brilliant young brother-in-law, and, as we have seen, had spent the years since Constantine’s accession steadily strengthening his own power-base around the Mediterranean. As early as 306, before he and his father had even established themselves in Italy, he had adopted the title of ‘Prince of the Romans’ and had had himself proclaimed by the Praetorian Guard in Rome; now, five years later, he was as powerful as any of his three rivals – powerful enough, indeed, to take his father’s death as a pretext for openly declaring his hostility to Constantine, branding him a murderer and a rebel, and ordering his name to be removed from all inscriptions and commemorations throughout Italy.

War, clearly, was unavoidable; and immediately on receiving the news of Galerius’s death Constantine began to make his preparations. Before marching against his adversary, however, he had to come to an agreement with Licinius, to whom the territories seized by Maxentius properly belonged. Fortunately for Constantine, Licinius could not lead an army himself to reclaim them, being already fully occupied in maintaining his position against Maximin Daia in the East; he therefore seems to have been only too happy for Constantine to undertake the reconquest of Italy on his behalf. The agreement was sealed by another betrothal – this time of Licinius himself to Constantine’s half-sister Constantia.

His diplomatic ground prepared, Constantine set off in the autumn of 311 for Colmar, where he spent the winter making his plans and preparing supplies for his army. Zosimus tells us that it consisted of 8,000 cavalry and some 90,000 infantry. It was probably only about a third of the total manpower available to him, but Gaul could not be left ungarrisoned. Anyway, he had a fair idea of Maxentius’s strength and he believed that these numbers would suffice. To make doubly sure, he himself assumed the supreme command; and, in the early summer of 312, he marched.

The factual story of Constantine’s Italian campaign and his overthrow of Maxentius can be quickly told. Crossing the Alps over the Mont-Cenis pass, he took Susa – the first town of any importance that lay on his route – by storm, refusing however to allow his soldiers their normal rights of plunder and pillage. They were, he told them, not conquerors but liberators. Outside Turin, the going was a good deal harder: Maxentius’s army here included a number of units of clibinarii, horsemen who, together with their mounts, were heavily armed and armoured in a manner which was probably derived from the Persians and which, a thousand years later, was to be imitated and developed in medieval chivalry. But even they were obliged to yield as groups of Constantine’s strongest men advanced upon them, swinging huge iron-bound clubs at shoulder height; and when they retreated in disorder to the city walls the citizens refused to open the gates to let them in. So Turin fell; then Milan; then – though only after heavy fighting – Brescia and Verona. Constantine continued his eastward drive as far as Aquileia, not far short of Trieste; only there did he turn, swinging back through Ravenna and Modena and southward towards Rome.

Throughout the long advance, Maxentius had remained in his capital – where, according to most of the Christian and even one or two of the pagan historians, he spent his time in ever more revolting occult practices: casting spells, calling up devils, even sacrificing unborn babies in his efforts to avoid his approaching fate. Such stories can be largely discounted; for all his faults, Maxentius had never lacked courage. Given his trusted Praetorian Prefect Ruricus Pompeianus and several excellent provincial generals (although, sadly for him, none of them proved as good as Constantine) his decision to stay in Rome had been, strategically, a perfectly sound one. But now, with Constantine’s army approaching and Pompeianus killed in battle, he took personal command and marched out of the city with the last, and best, of his reserves.

The two armies met on 28 October 312 – the seventh anniversary of Maxentius’s seizure of power – at Saxa Rubra, the ‘red rocks’ on the Via Flaminia some seven or eight miles north-east of Rome, where the little river Cremera flows into the Tiber;[4] and it was here, as later legend has it, just before or perhaps even during the battle, that Constantine experienced his famous vision. As Eusebius describes it:

… a most marvellous sign appeared to him from heaven, the account of which it might have been difficult to receive with credit, had it been related by any other person. But since the victorious Emperor himself long afterwards declared it to the writer of this history when he was honoured with his acquaintance and society, and confirmed his statement by an oath, who could hesitate to accredit the relation, especially since the testimony of after-time has established its truth? He said that at about midday, when the sun was beginning to decline, he saw with his own eyes the trophy of a cross of light in the heavens, above the sun, and bearing the inscription Conquer by This (Hoc Vince). At this sight he himself was struck with amazement, and his whole army also.[5]

The Chi-Rho symbol / Dylan Lake, Wikimedia Commons

Inspired, it is said, by so unmistakable an indication of divine favour, Constantine routed the army of Maxentius, driving it southward to where the Tiber takes a sharp turn to the west and is crossed by the old Milvian Bridge.3 Next to this bridge – which was extremely narrow – Maxentius had constructed another on pontoons, over which he could if necessary make an orderly retreat and which could then be broken in the middle to prevent pursuit. Over this his shattered army stampeded, the soldiers now fleeing for their lives, Constantine’s men hard on their heels. They might still have escaped, had not the engineers in charge of the bridge lost their heads and drawn the bolts too early. Suddenly the whole structure collapsed, throwing hundreds of men into the fast-flowing water. Those who had not yet crossed made blindly for the old stone bridge, now their only chance of safety; but, as Maxentius had known, it was too narrow. Many were crushed to death, others fell and were trampled underfoot, still others were flung down by their own comrades into the river below. Among the last was the usurper himself, whose body was later found washed up on the bank. His severed head, stuck on a lance, was carried aloft before Constantine as he entered Rome in triumph the following day. Later it was sent on to North Africa as a warning. Meanwhile the name of Maxentius was erased from all public monuments, just as his conqueror’s had been in the previous year.

The Battle of the Milvian Bridge made Constantine absolute master of all Europe from the Atlantic to the Adriatic, from Hadrian’s Wall to the Atlas. It also marked, if not his actual conversion to Christianity, at least the moment when he set himself up as a protector and active patron of his Christian subjects. Not only, during his two and a half months in Rome, did he generously subsidize from his private purse twenty-five already existing titular churches and establish several new ones; he also instructed his provincial governors to do likewise throughout his dominions. On his departure from the city he presented the newly elected Pope Melchiades with the old palace of the Laterani family on the Coelian Hill which the Empress Fausta – who had joined him soon after his arrival – had occupied during her stay. It was to remain a papal palace for another thousand years. Next to it he ordered the building, at his own expense, of the first of Rome’s Constantinian basilicas, St John Lateran, still today the Cathedral Church of the city. Significantly, it was given an immense free-standing circular baptistery: there was to be a formidable increase in the rate of conversions during the years to come.[6] To what extent, therefore, did the vision of the Cross that the Emperor is said to have experienced near the Milvian Bridge constitute not only one of the decisive turning-points of his life – comparable to that experienced by St Paul on the Road to Damascus – but also, in view of its consequences, a watershed of world history? The question is not an easy one to answer, and before we can even attempt to do so we must ask ourselves another: what actually happened? The earliest version of the story is that of our second principal source for the period, the Christian scholar and rhetorician Lactantius who, having somehow survived the persecutions, was at about this time appointed by Constantine to be tutor to his son Crispus. Whether or not he was already a member of the imperial entourage, Lactantius would have had plenty of opportunities shortly afterwards to question the Emperor directly about what took place. Writing probably within a year or two of the event, he records:

Constantine was directed in a dream to cause the heavenly sign to be delineated on the shields of his soldiers, and so to proceed to battle. He did as he had been commanded, and he marked on their shields the letter X, with a perpendicular line drawn through it and turned round at the top, being the cypher of Christ.[7]

He says no more. We have no mention of a vision, only of a dream. There is not even any suggestion by this devout Christian apologist that the Saviour or the Cross ever appeared to the Emperor at all. As for ‘the heavenly sign it was simply a monogram of chi (X) and rho (P), the first two Greek letters in the name of Christ, that had long been a familiar symbol in Christian inscriptions.

Perhaps more significant still is the fact that Eusebius himself makes no reference to either a dream or a vision in the account of the battle which he gives in his Ecclesiastical History of about 325. It is only in his Life of Constantine, written many years later after the latter’s death, that he produces the passage quoted above, following it up with a rather fuller version of Lactantius’s story in which he tells how, on the night after the vision, Christ appeared to the Emperor in a dream and ordered him to have a standard made in the likeness of the sign that he had seen in the heavens, ‘and to use it as a safeguard in all engagements with his enemies’. This, Eusebius tells us, Constantine did on the very next day. The result, which was known as the labarum, consisted of a cross fashioned from a gold-encrusted spear, surmounted by a wreath encircling the sacred monogram. When Eusebius saw it some years later a golden portrait of the Emperor and his children had been suspended, somewhat surprisingly, from the cross-bar.

Constantine’s vision, by Raphael, c.1508 / Museum of Vatican, Rome, Wikimedia Commons

What conclusions, then, are we to draw from all this? First, surely, that the vision of the Cross above the battlefield – that vision that we see endlessly depicted, on canvas and in fresco, in the churches and art galleries of the west – never occurred. Had it done so, it is unthinkable that there should not be a single reference to it in any of the contemporary histories until the Life of Constantine. The Emperor himself never seems to have spoken of it – except, apparently, to Eusebius – even on those occasions when he might have been expected to do so. Soon after his death, too, we find his son, Constantius II, being assured by Bishop Cyril of Jerusalem that the sight of a cross, recently traced in the sky by meteors, was a greater grace even than the True Cross found by his grandmother Helena in the Holy Land; could the Bishop possibly have omitted to mention Constantine’s vision had he known of it? Finally there is Eusebius’s specific statement that ‘the whole army . . . witnessed the miracle’. If that were true, 98,000 men kept the secret remarkably well.

There can be little doubt, on the other hand, that at a certain moment shortly before the fateful battle the Emperor underwent some profound spiritual experience. Lactantius’s bald account may well be substantially true; but experiences of this kind are not necessarily attended by such easily describable manifestations as dreams. There are indications that Constantine had been in a state of grave religious uncertainty since his execution of his father-in-law Maximian two years before, and was increasingly tending towards monotheism: after 310 his coins depict, in place of the old Roman deities, one god only – Helios or, as he was more generally known, Sol Invictus, the Unconquered Sun – of whom Constantine also claimed to have had a vision some years before, while fighting in Gaul. Yet this faith too – by now the most popular and widespread in the entire Empire – seems to have left him unsatisfied; Eusebius tells how, on his journey into Italy, knowing that he was shortly to fight the most important battle of his life – that on which his whole future career would depend – he prayed fervently for some form of divine revelation. No man, in short, was readier for conversion during that late summer of 312 than was Constantine; and it is hardly surprising that, up to a point at least, his prayers were answered.

If we accept this hypothesis Eusebius’s story becomes a good deal easier to understand, revealing itself less as a deliberate falsehood than as a possibly unconscious exaggeration, and less the fault of the writer than that of the Emperor himself. Throughout his life, and particularly after the Milvian Bridge, Constantine cherished a strongly developed sense of divine mission. In later years this sense grew ever more pervading; what then could be more natural than that, looking back on the great events of his life as it neared its end, he should have allowed his memory to add a gentle gloss here and there? In his day the existence of miracles and heavenly portents was universally accepted; from the reflection that he could have had a vision and that, in the circumstances, he should have had a vision, it was but a short step to the persuasion that the vision had actually occurred. And Eusebius would have been the last person to cross-examine him.

One question, however, remains to be answered: how complete was Constantine’s conversion? There is no doubt that from 312 onwards the Emperor saw himself as supreme guardian of the Christian Church, responsible for its prosperity and welfare; on the other hand his coins continued, at least until 324, to depict him as a companion of the Unconquered Sun and – more significant even than this – he still jibbed at the prospect of his own baptism, which he was to continue to postpone until he lay on his deathbed a quarter of a century later. This reluctance may to some extent have been due to political considerations; he was anxious not to alarm those of his subjects who still clung to the old gods. But he certainly did not hesitate to give mortal offence, during his stay in Rome, by refusing to take part in the traditional procession to the Capitol for the sacrifice to Jupiter.

The truth is probably rather more complicated: that while Constantine felt a genuine sympathy towards Christianity and genuinely believed the God of the Christians to have been responsible for his mystical experience (whatever that may have been) on the way to the Milvian Bridge, he was not yet ready to embrace the Christian religion in toto. While by now almost certainly accepting the concept of the Summus Dens, the Supreme God, he was perfectly ready to believe that this God might manifest himself in several different forms: as Apollo, or Sol Invictus, or Mithras (whose cult was still popular, especially in the army), or indeed the God of the Christians. Of all these manifestations he may have preferred the last, but as a universal ruler, feeling himself to be above all sects and hierarchies, he saw no reason not to keep his options open.

The Triumphal Arch of Constantine / Photo by Livioandronico2013, Wikimedia Commons

And the Roman Senate agreed with him. To celebrate his victory over Maxentius and his re-establishment of law, order and the imperial administration in the city, they erected in his honour the great triumphal arch that still stands a little to the south-west of the Colosseum. Much of its relief decoration is in fact reused, having previously served as part of various earlier monuments dedicated to Domitian, Trajan, Hadrian and Marcus Aurelius; Gibbon describes the whole structure as ‘a melancholy proof of the decline of the arts, and a singular testimony of the meanest vanity’. The inscription, however, dates explicitly from the time of Constantine. In translation, it reads:


Instinctu divinitatis: the phrase is a curious one, and must have been deliberately chosen for its ambiguity. There is no mention of Christ, nor of the Cross; no indication, even, of the precise divinity referred to. Yet Constantine must certainly have approved the text before it was passed to the stone-carvers. It is only natural that he should have been treading warily, as doubtless were the senators who drafted the inscription in the first place; one suspects, none the less, that his approval was not unwillingly given, since he himself had as yet made no final commitment to any one god. Instinctu divinitatis: he could not have put it better himself.

Apart from the triumphal arch – and the colossal statue of the seated Emperor, seven times life-size, which was placed in the remodelled (and hastily renamed) Basilica of Maxentius and of which the terrifying, staring, nine-ton head survives in the Capitoline Museum – the Roman Senate showed to Constantine, during the last two months of 312, one further mark of favour. They proclaimed him Supreme Augustus. It was in this capacity that he left the city in early January 313 for Milan, where he had arranged to meet Licinius.

The Augusti had three principal issues to discuss. The first was the future of Italy. Theoretically it formed part of that area of the Empire which was subject to Licinius, but the latter had not raised a finger to assist Constantine in its recapture and cannot seriously have expected that his colleague would now freely hand it back to him. Next was the question of religious toleration and, in particular, the future status of the Christians. It was obvious that a single policy should prevail throughout the Empire; at the same time the elderly Licinius was unlikely to feel as well disposed towards Christianity as his fellow-Emperor, and some sort of understanding would have to be reached between them. Finally there came the problem created by the third living Augustus, Maximin Daia.

This odious young man – the exact date of his birth is unknown, but he seems still to have been in his early thirties – had started making trouble in 310 when, after five years as a Caesar, he had demanded the rank of Augustus. His uncle Galerius, sadly aware that with Constantine, Maximian and Maxentius all having claimed the title in the recent past it was in danger of becoming seriously devalued, had refused point-blank, offering him instead that of Filius Augusti; but Maximin Daia had angrily rejected this belittling alternative and had assumed the Augustan attributes of his own accord. On Galerius’s death he had seized the Eastern Empire as far as the Hellespont, from which point of vantage he had made continual trouble for Licinius in Thrace until, in the winter of 311—12on a barge in the middle of the Bosphorus, the two had patched up an uneasy truce. Moreover, he loathed Christianity. He had blatandy ignored his uncle’s Edict of Toleration in 311 and was still wallowing in Christian blood – even on occasion sending his soldiers in pursuit of Christian refugees over the imperial borders into Armenia, whose King was consequently on the point of declaring war against him.

The talks between the two Emperors passed off amicably enough. Licinius seems to have accepted with a good grace that Constantine should keep the territories that he had conquered, and was duly married – according to what rite is unfortunately not recorded – to Constantia.

Bust of Emperor Maximin Daia / Photo by shakko, Pushkin Museum, Wikimedia Commons

Where the Christians were concerned, the new brothers-in-law agreed the final text of a further edict, confirming that of Galerius and granting Christianity full legal recognition throughout the Empire. Before this could be promulgated, however, news reached Milan that brought the meeting to an abrupt and premature end: Maximin Daia had broken the truce of the previous winter, crossed the straits with an army – estimated by Lactantius at 70,000 – and seized the little town of Byzantium on the European shore. Licinius moved fast. Taking the small force that he had with him at Milan, summoning reinforcements to join him in Illyria and Thrace and picking up what further units he could along his route, he left immediately for the East. By late April we find him a few miles from Heraclea Propontis, another small settlement on the Marmara to which Maximin was laying siege; and on the last day of the month the two armies met at a spot known as the Serene Fields, some eighteen miles outside the town.

Outnumbered though he was, well past his own youth and with his men exhausted from the length and speed of their march, Licinius proved by far the more brilliant general of the two. Maximin’s army was ignominiously routed, he himself fleeing from the field disguised as a slave. He finally made his way to Cilicia, where he died the following year – as disagreeably, Lactantius is happy to inform us, as his fellow-persecutors:

He swallowed poison … which began to burn up everything within him, so that he was driven to distraction by the intolerable pain; and during a fit of frenzy, which lasted four days, he gathered handfuls of earth, and greedily devoured it. After various excruciating torments he dashed his forehead against the wall, and his eyes started out of their sockets … In the end he acknowledged his own guilt and implored Christ to have mercy on him. Then, amidst groans like those of one burnt alive, did he breathe out his guilty soul in the most horrible kind of death.[8]

Licinius, meanwhile, had made his triumphal entry into the eastern capital, Nicomedia – where, somewhat belatedly on 13 June, he promulgated the edict on which he and Constantine had agreed at Milan:

When I, Constantine Augustus, and I, Licinius Augustus, had come under happy auspices to Milan, and conferred together on all matters that concerned the public advantage and welfare … we resolved to make such decrees as should secure respect and reverence for the Deity; namely to grant both to the Christians and to all others the right freely to follow whatever form of worship might please them, to the intent that whatsoever Divinity dwells in heaven might be favourable to us and to all those living under our authority.[9]

Here, once again, is a text that bears all the signs of cautious drafting. Still we find no mention of Jesus Christ, only of ‘the Christians’ as a sect; and – although they are the only group specifically named – it is made abundantly clear that ‘all others’ (the Manicheans, for example) are also included in what is, in effect, a general edict of toleration. As to the reference to ‘whatsoever Divinity dwells in heaven’ (quo quicquid est divinitatis), this phrase may have been insisted on by the pagan Licinius; but a comparison with the inscription on the triumphal arch suggests that it probably corresponded fairly closely with Constantine’s own thinking. In one respect only does the ordinance discriminate in favour of the Christians: they alone are to have restored to them all their property – land, churches and chattels – confiscated during the Persecutions. But, it should be remembered, no other sect had suffered comparable losses.

The removal of Maximin Daia had the effect of polarizing the Empire. Once again there were only two Augusti, Constantine in the West and Licinius in the East – where he immediately instituted a reign of terror. Not only were all his predecessor’s chief ministers executed; so too were numerous members of Maximin’s family – which, in view of the various marriage alliances concluded among past Augusti and their Caesars, included the families of Diocletian and Galerius. Even the latter’s widow Valeria, even his mother-in-law Prisca, Diocletian’s widow whom Galerius had entrusted on his deathbed to Licinius’s care, were shown no mercy; both were arrested in their homes at Thessalonica and put to the sword.

The reason for this blood-bath was not simply vengeance, nor yet vindictiveness; it was the conviction on the part of Licinius that there was room in the Empire for one ruling family only – the family of Constantine, of which he himself, since his marriage to Constantia, was a member. This conviction did not, however, bind him closer to his co-Augustus; indeed, the honeymoon inaugurated at Milan was to prove all too short. Within six months of the two Emperors’ departure from the city, Licinius had entered into a conspiracy against Constantine – though fortunately it was brought to light before any harm was done. Soon afterwards, in the early summer of 314, he ordered the removal of all his colleague’s statues and portraits from the town of Aemona – now Ljubljana – on the border of the Italian Province.

Map of the Roman Empire during 116, the province Pannonia highlighted / Wikimedia Commons

It was, in effect, a declaration of war. Constantine, who had returned to Gaul, immediately marched south-east with some 30,000 men into the Pannonian plain, to meet his adversary near Cibalae – the present Vinkovci – in the Sava Valley. The battle was joined before dawn on the morning of October: Licinius fought with determination and courage but was finally obliged to yield, his retreating army being pursued by Constantine right across the Balkan peninsula to Byzantium. There at last the two Emperors came to an understanding: Licinius agreed to give up all his dominions in eastern Europe – they included Pannonia and the whole of what we now know as the Balkans – with the single exception of Thrace; in return, Constantine undertook to recognize his authority throughout Asia, Libya and Egypt.

The two Emperors were friends again; but they did not remain so for long. Indeed, the story of the next decade is one of a steady deterioration in the relations between them. In 317 Constantine named his two young sons – Crispus, the fourteen-year-old child of his marriage to his first wife Minervina, and another Constantine, the infant son of the Empress Fausta, who was hardly out of his cradle – as joint Caesars of the West; simultaneously, Licinius at Nicomedia conferred the same rank on his own natural son, Licinianus; but these moves were doubtless concerted in advance and do not necessarily reflect any particular rivalry. By the following year, however, Constantine had moved his court from Sirmium to Serdica, the modern Sofia – a curious choice of capital for a ruler whose domains extended to the Straits of Gibraltar and beyond, and one which was logically justifiable only on the assumption that it was from the Eastern Empire, rather than from the Gauls or the Franks or the Donatists in North Africa, that trouble was to be expected.

In fact, that trouble was to be largely of Constantine’s making. His apologists do their best to lay the blame on Licinius for his duplicity and faithlessness as well as for his undeniably growing hostility to the Christian religion: from 320 or thereabouts he imposed a ban on all episcopal synods, expelled a large number of bishops and priests (though by no means all of them) and dismissed from his household staff all who would not sacrifice to the pagan gods. By now, however, it was becoming clear that Constantine was determined to put an end to Diocletian’s disastrous division of the Empire and to rule it alone. From 320, in defiance of recent tradition, he did not even include an easterner as one of the two annually elected Consuls, naming instead himself and his younger son; in321 both his sons were named.[10] That same year he began to gather together a huge war fleet, and to enlarge and deepen the harbour at Thessalonica in readiness for its reception.

Licinius also began to prepare for war, and for some time the two Augusti watched each other, waiting. In the autumn of 322, however, while repelling an attack by the Sarmatians – a nomadic barbarian tribe normally inhabiting the regions north of the lower Danube – Constantine, inadvertently or otherwise, led his army into Thrace. Licinius made a violent protest, claiming that this was a deliberate infringement of his territory for purposes of reconnaissance, and an obvious prelude to a full-scale invasion; he then advanced, with a force estimated at some 170,000, up to Adrianople – the modern Edirne. When Constantine marched, he would be ready to receive him.

It was in the last week of June 323 that the army of the West crossed the Thracian border; and on 3 July, on a broad, sloping plain just outside Adrianople, it found itself confronted by that of the East. Constantine’s force was slightly the smaller of the two; but it was largely composed of hardened veterans, who had little difficulty in wearing down their comparatively inexperienced opponents. Once again Licinius fought with conspicuous courage, ordering a retreat only when some 34,000 of his men lay dead on the field. Then he withdrew to Byzantium, just as he had done nine years before. This time, however, he sought no terms; instead, he declared Constantine deposed, named his chief minister, one Marcus Martianus, as Augustus in his place, and settled down to withstand a siege.

Constantine for his part dug himself in – reflecting yet again, one is tempted to think, on the strategic position and superb natural defences of the little town – and waited patiently for his fleet. He had entrusted its command to his son Crispus, now a man of twenty, married and a father, with five years’ campaigning experience already behind him; it consisted of some 200 thirty-oared war galleys backed up, we are told, by 2,000 transports. To defend the Hellespont, Licinius could boast a yet more numerous armada of some 350 vessels under his admiral, Abantus; inexplicably, however, this man had decided to take his stand, not at the Aegean end of the strait where his superior numbers could be put to proper advantage, but at its north-eastern extremity where it widens into the Sea of Marmara. When the invasion fleet arrived, it attacked at once. The ensuing engagement lasted two full days, but at last Crispus’s lighter, faster and more manoeuvrable ships, having sunk 150 of the defenders, smashed their way through and sailed on to Byzantium.

The moment he heard of their advance, Licinius slipped out of the town and crossed the Bosphorus into Asia; but Constantine was ready. Swiftly embarking his army in the newly arrived transports, he set off immediately in pursuit, and on 18 September scored another major victory at Chrysopolis (now Uskudar or, more familiarly, Scutari). Licinius hastened back to his capital at Nicomedia; great as his losses had been, his spirit was not yet broken and he had every intention of making a last stand. It was his wife who dissuaded him. If he surrendered now, she pointed out, he might yet escape with his life. The next day she herself went off to see her half-brother in his camp to plead with him on her husband’s behalf.

And Constantine granted her request. He summoned Licinius, greeted him with every sign of cordiality and even invited him to dinner. Then he sent him into exile at Thessalonica, under close surveillance but in a degree of comfort appropriate to his rank. He showed similar magnanimity to his own self-styled successor Martianus, whom he simply banished to Cappadocia. Particularly in view of Licinius’s conduct when he himself had taken over the Eastern Empire, such clemency was remarkable indeed; alas, it did not last. A few months later, both men were summarily put to death.

The reasons for the Emperor’s sudden change of heart are unknown. It is possible, as the Christian historian Socrates asserts – though he was writing a century later – that Licinius had been up to his old tricks again and was conspiring with the barbarian tribes (presumably the Sarmatians) for Constantine’s murder and his own return to power; possible, but hardly likely. A far more probable solution to the problem can be found in the words of a prayer which Constantine wrote himself at about this time and circulated throughout the Empire in the form of an encyclical letter. After a long opening section in which he describes and deplores the previous Persecutions, ‘my own desire is,’ he continues, ‘for the general advantage of the world and all mankind, that Thy people should enjoy a life of peace and undisturbed concord.’

It was true; after the war against Licinius and for the rest of his life we find him repeating these sentiments again and again and striving continually, at whatever cost, to avoid war or anything that might lead to it. By now, however, he can have had no doubts left in his mind that, if the Roman Empire were to remain at peace, it must continue to be united under a single head; and he must strongly have suspected that Licinius would never be content to remain for long in obscurity. The Empire, in short, was not – for all its vastness – big enough for both of them; and if the promise of peace required the elimination of the only two other claimants to the title of Augustus, it was surely cheap at the price.


  1. Euscbius, De Vita Constantini, 1, 19.
  2. Soon after his retirement, Diocletian received a message from the ever-restless Maximian, encouraging him to resume the purple. Gibbon tells us that ‘he rejected the temptation with a smile of pity, calmly observing that, if he could show Maximian the cabbages which he had planted with his own hands at Salona, he should no longer be urged to relinquish the enjoyment of happiness for the pursuit of power’.
  3. Euscbius, Historia Exclesiastica, VIII, 16.Euscbius, Historia Exclesiastica, VIII, 16.
  4. The site is now known as Grotta Rossa. De Vita Constantini, 1, 28.
  5. Originally built in 109 BC, the Pontc Milvio still stands, though it has been many times rebuilt and restored – most recently by Pius IX in 1850 after Garibaldi had blown it up.
  6. i Constantino’s baptistery no longer stands. Its present octagonal successor dates from the time of Pope Sixtus III.
  7. i Dt Mortibus Ptrseculorum, Chap. xliv.
  8. Lactantius, De Mortibus Persecutorum, Chap. xlix.
  9. Lactantius, De Mortibus Persecutorum, Chap, xlviii.
  10. This dual consulate was one of the oldest and most venerable institutions of the Roman Republic, in which the Consuls were, during their year of office, the supreme civil and military magistrates of the State. By late imperial days the title had become purely honorary, with the two chosen Consuls at liberty, in Gibbon’s memorable phrase, ‘to enjoy the undisturbed contemplation of their own greatness’; each year, however, was known by the names of the Consuls appointed for it, and the office itself remained so elevated as to be held by only the very highest dignitaries not infrequently the Emperors themselves: Constantine’s own consulate in 320 was in fact his sixth.

From Byzantium: The Early Centuries, by John Julius Norwich (Knopf, 03.18.1989), published by Erenow, public open access.



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