Constantine the Great: The Years 311-312

Bronze head of Constantine (Capitoline Museums, Rome).

On paper Galerius was the senior augustus within the Tetrarchy. We do not know his exact age, but at the beginning of 311 he was well into his fifties. The old emperor had become a shadow of a man, perhaps as a result of colon cancer. That is at least how modern historians interpret the downright disgusting descriptions that have been passed on to us by the Christian authors Lactantius and Eusebius.[1] Lactantius’ account is a litany of ulcers, bleedings, putrefaction and unbearable stench, while the account of Eusebius, which includes abscesses, worms and the smell of death, is certainly as revolting. The two authors were no doubt exaggerating; as Christians they had a bone to pick with the man they held responsible for the persecution of Christians. Nevertheless, it was crystal clear that the emperor was seriously ill and did not have long to live. There was nothing his personal physicians could do for him. As he felt the hour of his death approaching, Galerius took a remarkable step: on 30 April 311 he issued an edict that put an end to the persecution of Christians that had started eight years previously under Diocletianus.

Tolerance or intolerance

The so-called Edict of Tolerance stipulated that Christians could be Christians again – ut denuo sint christiani – and that they were once again allowed to hold their meetings. This was all under the condition that they would pray for the welfare of the Roman Empire and that they did not disturb public order, ne quid contra disciplinam agant.[2] The latter condition gives a fair indication why Diocletianus had started the persecutions in the first place. It is difficult to say why Galerius now decided to end them. Perhaps he simply concluded that the persecutions had been largely unsuccessful, as indeed they had not led to mass apostasy. Another possibility is that he feared the power of the Christian God, who seemed to have held his ground effortlessly while the emperor was now struggling against death. A few days after issuing the edict Galerius died. He found his final resting place in Romuliana (Gamzigrad in present-day Serbia), where he had built a splendid palace complex that had been named after his mother Romula.

Follis of Licinius (source: Classical Numismatic Group, Inc.).

Now that Galerius had died, Licinius and Maximinus Daza lost little time to take possession of his territories. Licinius occupied the Balkan provinces while Daza marched into Asia Minor. A war between the two emperors was looming, but in the end the men decided to negotiate and decided to make the Bosporus the border between their two respective realms. Peace had been made, but it was a brittle peace. Licinius soon began courting Constantine, while Daza worked on his relationship with Maxentius, the ruler of Italy and North Africa. Constantine, who had for a long time been planning an invasion of Italy, was eager to accept an alliance with Licinius. In the autumn of 311 the men agreed that Licinius would marry Constantine’s Christian half-sister Constantia. She was a daughter of Constantius Chlorus and Theodora. Presumably she was about seventeen years old at the time. Licinius did not marry Constantia immediately; the formal wedding would take place later.

The Edict of Tolerance had been intended for the whole Roman Empire. In the west it had little effect, for the simple reason that the persecution of Christians had never gained momentum there. After Constantius and Constantine had become augusti in 305/306 the persecution had in fact ceased altogether. Maxentius had never persecuted Christians either, no matter what later Christian authors would claim. But in the east, especially in the diocese of Oriens, this was all very different. In Egypt, Syria and Palestine the prisons opened their doors and the Christians celebrated. Not only had they had they stood firm, they had even become stronger than ever. Maximinus Daza, however, largely ignored the edict, and towards the end of 311 he resumed the persecutions, which he mostly left to the magistrates of the major cities. The number of victims cannot have been large, for as always the goal of the persecutions was to bully, intimidate or – if necessary – torture the Christians into making pagan sacrifices. Nevertheless, there were in fact a couple of eminent Christian martyrs, such as patriarch Peter of Alexandria, the theologist Lucianus of Antioch and – perhaps – bishop Anthimus of Nicomedia.

Constantine attacks

In November of the year 311 Diocletianus passed away, the founder of the Tetrarchy. His creation was now all but dead and buried. Three rulers called themselves augustus: Constantine, Licinius and Maximinus Daza. A fourth ruler, Maxentius, resided in Rome clandestinely. Maxentius had just, perhaps in 310 or 311, managed to recover North Africa, where the vicarius Lucius Domitius Alexander had been proclaimed emperor. Alexander had been defeated by Maxentius’ praetorian prefect Gaius Rufius Volusianus. According to Aurelius Victor, the prefect had brought along just a handful of cohorts, but these quickly proved to be very effective.[3] Volusianus’ veterans cut Alexander’s inexperienced troops to pieces and then celebrated their victory by sacking the city of Carthage. Alexander had fled and entrenched himself in Cirta, the capital of Numidia. During the subsequent siege this city was also heavily damaged, so damaged in fact that it had to be rebuilt by Constantine later and was then named Constantina after him. Cirta was eventually captured and Alexander strangled to death. Although Maxentius was deeply hated in North Africa for the atrocities that he had committed there, he had now won back control of the vital grain export from Africa to Rome.

In the Spring of 312 Constantine left his capital of Augusta Treverorum (Trier) and marched his army to Lugdunum (Lyon) and then Vienna (Vienne) for an invasion of Italy. Strictly speaking Maxentius was still his brother-in-law (as he was the brother of his wife Fausta), but Constantine had long ago decided to expand his territories at all costs. According to Zosimus, Constantine’s army was composed of 90,000 foot soldiers and 8,000 horsemen.[4] This may indeed have been the total number of soldiers available to Constantine in his own realm, but it is rather unlikely that he took all these men with him on campaign. After all, the Rhine border needed to be protected and troops were also necessary in Spain and Britannia. It therefore seems more realistic to assume that his army numbered some 35-40,000 men. Maxentius had 170,000 foot soldiers and 18,000 horsemen according to Zosimus. This number is no doubt way too high, but the assumption that the emperor had an army with a total strength of some 100,000 men, including almost 10,000 praetorians, seems quite reasonable. It should be noted that Maxentius had to split this large force into many smaller armies to protect Rome and the cities of Northern Italy. Moreover, he had to be prepared for an attack by his other enemy Licinius, Constantine’s ally who had already invaded Italy back in 309.

Constantine’s campaign against Maxentius (source: Ancient World Mapping Center. “À-la-carte”; CC BY 4.0).

After reaching Italy, Constantine first besieged and captured the town of Segusio (now Susa in Piemonte).[5] Then his cavalry won a victory over Maxentius’ heavy cavalry near Augusta Taurinorum (Turin). Constantine promptly took the city itself as well and moved on to Mediolanum (Milan), which was occupied without any bloodshed. The next target was Brixia (Brescia), where a new engagement between the cavalry of the two armies took place. Again Constantine was victorious and again one of his rival’s cities fell into his hands. But Brixia was just a minor city compared to Verona, Constantine’s next target. He put the city under siege and fought against the praetorian prefect Ruricius Pompeianus, Maxentius’ most important general. Pompeianus commanded an army of perhaps 40-50,000 men. A major battle was subsequently fought, which saw huge losses on both sides. In the end, however, Constantine won another victory, while Pompeianus was killed. Verona capitulated not long after the battle, and was soon followed by Mutina (Modena) and Aquileia.

Constantine the Great besieges Verona (Arch of Constantine, Rome).

A dream or vision

Chi-rho sign on a shield (San Vitale, Ravenna).

After his resounding victory Constantine and his army marched from Mutina to Ravenna along the Via Aemilia. He then took the road from Ravenna to Ariminum (Rimini) to get onto the Via Flaminia. From Fanum Fortunae (Fano), he could advance on Rome by simply following the road to the south. Presumably the emperor made his camp about twenty kilometres north of the Eternal City, at Malborghetto, where later a four-sided arch would be erected. It was now the end of October of the year 312 and the decisive battle against Maxentius was about to be fought. According to tradition, Constantine had a dream or vision prior to the battle, but even his contemporaries could not agree on what it was that he had supposedly seen. According to Lactantius, who wrote around 314, the emperor was commanded in a dream to paint the ‘heavenly sign’ (caeleste signum dei) on the shields of his soldiers. This sign was an X punctured by a vertical line that was rounded at the top (transversa X littera summo capite circumflexo).[6] In other words, it was most likely the famous chi-rho sign, the Greek letters X and P that together formed the first two letters of the name of Christ.

In another Christian source, the work of Eusebius of Caesarea, we find an account that is both quite different and much more extensive. In his Church History, written in 315-316, Eusebius mentions neither a dream nor a vision, but in his Life of Constantine from ca. 340 he speaks of a vision of a “trophy of a cross of light” above the sun.[7] Supposedly this sign had been visible around noon, and the whole army had been a witness. Moreover, the sign was said to have been accompanied by the Greek words toutoi nika, “conquer in this” (later often mangled into Latin as in hoc signo vinces). After the vision Christ had reportedly also appeared to Constantine in a dream, commanding him to replicate the “trophy of a cross of light” and to carry it with him in battle. And so Constantine had the labarum made, his battle standard topped by the letters chi and rho (XP). Eusebius claims that he had heard the story mentioned in his Life of Constantine from the emperor himself. Constantine had according to the writer sworn an oath that the story was true. It is possible that this story was the official version of events, the version that Constantine himself wanted the public to embrace.

Constantine’s Vision of the Cross by Giacinto Gimignani (1606-1681), Lateran Baptistery.

One problem with Eusebius’ story is that chronologically he places it well before Constantine’s invasion of Italy.[8] It follows that the emperor supposedly had his vision and dream in Gaul and started his campaign with the labarum already in his army. In Lactantius’ version Constantine has his dream just before the battle with Maxentius in the vicinity of Rome. Modern historians often see similarities with a dream or vision that Constantine was said to have had around 310 in Andesina (Grand). There, according to an orator, the emperor saw how Apollo and Victoria, the goddess of victory, offered him laurel wreaths. This pagan vision was perhaps later given a Christian interpretation. Of course this is all speculation, and there is no law that stipulates that Roman emperors can have only one dream or vision in their lives. There are plenty of differences between the descriptions given by Lactantius and Eusebius and the story of the (pagan) orator. There may very well have been multiple dreams or visions, which may or may not have been imagined or faked by Constantine himself.

The Milvian bridge

On 28 October the decisive battle took place between Constantine and Maxentius, which is usually called the battle of the Milvian bridge (Pons Milvius). Maxentius could simply have copied his tactics that had been so successful during previous attacks by Severus and Galerius. If he had stayed in Rome, he could have waited to see his opponent dash himself to pieces against the formidable Aurelian walls from the third century. But on 28 October Maxentius had been on the throne for exactly six years. In Rome itself his popularity had plummeted, and when the Sibylline books had been consulted, the emperor had been told that on this day “an enemy of the Romans would perish”.[9] Maxentius was fully convinced that that enemy was Constantine. He took his praetorians to the Milvian bridge, which he had disassembled and replaced with a pontoon bridge. Once on the other side of the Tiber, he ordered his army to advance on Saxa Rubra (‘Red Rocks’), where the Via Flaminia entered a narrow pass. Constantine, however, had already led part of his army through the pass, and these troops now clashed with Maxentius’ vanguard.

The modern Milvian bridge.

The battle of the Milvian bridge was basically fought on the ten-kilometre stretch of terrain that separated Saxa Rubra from the Pons Milvius. In the end, Constantine won a hard-fought victory. Maxentius’ praetorians and his mounted bodyguard, the equites singulares augusti, gave their utmost. After all, their personal survival was at stake here. But slowly but surely Maxentius’ troops were pushed back to the bridge. There the emperor met his tragic end. The pontoon bridge could probably be dismantled by removing the middle segment. This would allow Maxentius’ army to safely withdraw to Rome. However, Lactantius claims that the bridge had already been demolished during the battle and that Maxentius was driven into the river, where he drowned. Zosimus and Eusebius also mention a mechanism to dismantle the bridge or to raise it, but both writers state or suggest that the bridge collapsed under the weight of the fleeing soldiers. Maxentius and many others fell into the water and were drowned. The sources are all in agreement that the emperor lost his life in the river Tiber. The heavy suit of armour that he was wearing made it impossible to stay afloat.[10]

Battle of the Milvian bridge; soldiers of Maxentius drown in the river Tiber (detail). Arch of Constantine, Rome.

Constantine and the Christians

One day after his victory, on 29 October, Constantine entered Rome in triumph. Maxentius’ body had by now been found and the slain emperor was posthumously decapitated. The severed head was then stuck on a spear and sent to North Africa, the part of the Roman world where Maxentius’ troops had so recently wreaked havoc. The name of the emperor was moreover removed from all monuments. Constantine for his part had captured a city with a large Christian population. We will never know how many Christians there were exactly, but there must have been several tens of thousands. The new ruler immediately disbanded the Praetorian guard and the equites singulares augusti, and subsequently donated the terrain where the barracks of the horse guards stood to bishop Melchiades (311-314) and the Christian community of Rome. The barracks were partially demolished. What was left of the buildings was filled up with earth to create a platform that would serve as the base for a splendid new basilica. The basilica was dedicated to Christ the Saviour and was – according to church tradition – consecrated on 9 November 324. It is currently known as San Giovanni in Laterano and serves as the cathedral of Rome.

Speech of Constantine in the Forum Romanum (Arch of Constantine, Rome).

Constantine did not formally convert to Christianity until 337, when he was on his deathbed. It is impossible to establish whether he already saw himself as a Christian as early as 312, but there can hardly be any debate that he began favouring the Christian community of Rome immediately after his victory over Maxentius. Later, but in any case before 326, the emperor commissioned monumental basilicas that were to be built over the presumed graves of the apostles Peter and Paul. He also donated valuable objects for the baptistery next to the basilica of the Saviour. Constantine can furthermore be associated with the construction of the church in the palace that is known as the Sessorium and possibly with the Basilica Apostolorum. By contrast, the emperor does not seem to have done anything for the traditional cults in the city. Not a single pagan temple built by Constantine is known, nor does the emperor seem have sacrificed to the traditional gods after 312.[11] Admittedly, Zosimus in his Historia Nova from the early sixth century mentions a sacrificial ceremony that supposedly took place on the Capitoline hill, but not only is his account muddled to the extreme, the writer also states that rather than respecting them Constantine completely disregarded the sacred ceremonies.[12]

Solar wheels or rouelles (Musée d’Art et d’Histoire, Langres).

It is true that, even though Constantine’s Christian sympathies were obvious, the emperor continued to mint bronze and gold coins bearing the image of Sol Invictus, the Unconquered Sun, until 318 and 325 respectively. However, at the same time Constantine does not seem to have done anything for the temple of Sol Invictus in Rome, which had been consecrated by the emperor Aurelianus in 274. Constantine did not commission any renovations or expansions and did not gift any valuable items either. The chi-rho sign begins to appear on the emperor’s coins starting in 315, and according to Eusebius the two letters were also depicted on his battle helmet.[13] Non-Christians probably did not necessarily interpret the sign as a Christian symbol. The chi-rho sign was probably inspired by the six-armed star that symbolised the sun. This made the symbol quite acceptable for non-Christian soldiers in Constantine’s army, whether it was painted on the shields of the men or had become an integral part of the labarum. Soldiers from Britannia, Spain or Gaul might have seen the sign as “wheels of Taranis”, solar wheels or rouelles.

Around the year 312 there cannot have been many Christians in Constantine’s army yet, a few hundred at most. The vast majority of the soldiers were still followers of the traditional cults. This meant that Constantine, if he was a Christian at all, had to be careful at all times, so as not to step on any toes. It might also explain why he did not include any explicitly Christian references on the triumphal arch next to the Colosseum that he erected in honour of his victory over Maxentius (ca. 315). Part of the text on the arch are the words instinctu divinitatis – “inspired by the deity –, which may refer to just about any deity. The debate about Constantine’s relationship with Christianity will no doubt continue. However, one thing is certain: Christian or not, the man was first and foremost a Roman emperor, and his actions were always aimed at preserving and strengthening his position as emperor. Constantine would stop at nothing to achieve that goal.

The Colosseum with the Arch of Constantine next to it.


Primary sources

Secondary sources

  • Adrian Goldsworthy, The Fall of the West, p. 177-178 and p. 182-185;
  • Henk Singor, Constantijn, p. 237-292;
  • Timothy Venning, A Chronology of the Roman Empire, p. 642-645.

[1] Lactantius, De mortibus persecutorum, chapter XXXIII; Eusebius, Vita Constantini, Book 1.57.

[2] De mortibus persecutorum, chapter XXXIV.

[3] Aurelius Victor, De Caesaribus 40.

[4] Zosimus, Historia Nova, Book 2.15.

[5] I follow the reconstructions of Constantine’s campaign in Henk Singor, Constantijn, p. 272-275 and Timothy Venning, A Chronology of the Roman Empire, p. 644.

[6] De mortibus persecutorum, chapter XLIV.

[7] Eusebius, Vita Constantini, Book 1.28-31. Some modern historians interpret this as a halo around the sun.

[8] The invasion is discussed in Vita Constantini 1.37.

[9] De mortibus persecutorum, chapter XLIV.

[10] Epitome de Caesaribus 40.

[11] Henk Singor, Constantijn, p. 292.

[12] Historia Nova, Book 2.29. The author mentions a Spaniard named Aegyptius who supposedly enticed Constantine to embrace Christianity. Was Zosimus perhaps referring to bishop Ossius of Corduba?

[13] Vita Constantini, Book 1.31.


  1. Pingback:Constantine the Great: The Years 313-315 – – Corvinus –

  2. Pingback:Constantine the Great: The Years 316-323 – – Corvinus –

  3. Pingback:Arezzo: San Francesco – – Corvinus –

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.