Was Constantine a ‘Great’ Emperor?

The history of Rome and Europe was changed forever by these 8 key events. Does he deserve the title of Constantine the Great?

Apr 8, 2021By Kieren Johns, PhD Classics & Ancient History
constantine the great
Constantine the Great Commissions the Building of the Basilica of S. Giovanni in Laterano, Guiseppe Belloni, 1656-1685, Museum Kunstpalast, Düsseldorf; with Triumphant Entry of Constantine into Rome, Peter Paul Rubens, c. 1621, Indianapolis Museum of Art


With tongue presumably firmly in cheek, the unknown author of the collection of biographies known as the Historia Augusta purports to present his lives of the emperors from Hadrian to Carinus to two of the most influential Roman emperors of the early fourth century: Diocletian and Constantine. Towards the end of his Life of the unfortunate emperor Alexander Severus, who reigned from AD 222 until his death at the hand of his soldiers in 235, the unknown author digresses to address Constantine directly: “You are wont to inquire, most mighty Constantine, why it was that a man… became so great an emperor” (SHA Alex. Sev. 65.1). It is now believed that the author of the Historia Augusta was using these imperial biographies to entertain and scandalize a learned late fourth century readership, with texts stocked full of rumor, rhetoric, and knowing literary allusions. But the question raised here is striking, and maps onto a modern ambivalence about this emperor: what kind of emperor was Constantine really?



constantine marble bust
Marble portrait of the Emperor Constantine I, c. AD 325-70, Metropolitan Museum, New York


After all, how are we to assess an emperor whose life throws up a multitude of contrasts? An emperor who restored Rome and looked back to the celebrated rulers of old, but at the same time abandoned the vaunted imperial capital in favor of a new cosmopolis; a conquering general but one whose greatest triumphs came against his Roman compatriots; a man who bends the will of the divine to his own ends, but who that divine was remains debated. The story of Emperor Constantine’s rise and reign, a story of conflict, conspiracy, and Christianity, is pivotal to an understanding of later Roman history and the shape of Europe for centuries after.


1. Before Constantine Was Great: The Constantinian Dynasty In Britain

silver antoninus coin
A silver Antoninianus coin, with obverse portrait of Constantius, father of Constantine, with radiate crown; with reverse depiction of the Caesar greeting Galerius, his Tetrarchic equal, with a kneeling captive between them, struck at Sisica in Pannonia, AD 293, via American Numismatic Society


The story of one of Rome’s greatest emperors does not begin at Rome. The man history will remember as Constantine the Great was born Flavius Valerius Constantinus in c. AD 272, in the city of Naissus. This city (modern Niš) was located in the province of Moesia, encompassing an area of the Balkans south of the Danube, including Serbia. This means that, along with his father Constantius, Constantine was an Illyrian. This region had grown in significance over the third and fourth centuries, with a succession of emperors hailing from the region; today, this growing historical importance is celebrated by the suitably named ‘Roman Emperor’s Route’, a historical and archaeological tour of important sites in the area. Constantine’s youth, however, was not spent at Naissus. Instead, he was educated at the court of Diocletian, the emperor, where he was in some sense a hostage to the strained relationships of the Tetrarchy (see below). He was not, however, a prisoner. The young man was a prominent member of the court and actively involved in Diocletian’s campaigns in the east, receiving valuable military training and experience.

portrait of constantius chlorus
Portrait of Constantius Chlorus, father of Constantine, photographed by the author, Altes Museum, Berlin

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While Constantine was receiving an imperial education in the east, his father was campaigning in the west. He had been a member of Emperor Aurelian’s bodyguard in the late third century, fighting in the campaigns against the rebelling Palmyrene empire, and his successes saw his continued elevation through the ranks. In 288, he was appointed to act as the praetorian prefect in Gaul for the emperor Maximian, Diocletian’s colleague in power, becoming a Caesar, a junior co-emperor, in Diocletian’s division of the empire in AD 293 again, opening up the route for Constantine’s rise to power in the future. Notably, as Caesar, Constantinius had been dispatched from his capital at Augusta Treverorum (modern Trier, Germany) to quash another break-away empire and usurping emperor: Carausius. In AD 286, Carausius had declared himself emperor in Britain and northern Gaul, with the historian Eutropius under no illusion as to the danger this posed: “disorder thus prevailed throughout the world, while Carausius was taking arms in Britain”.

arras medallion
The Arras Medallion of Constantius I, with a reverse depiction of the city of London, represented by the kneeling woman on the reverse, pleading for clemency from the conquering Roman emperor who approaches the city gate, minted in Trier, British Museum


Constantius quashed the rebellion of Carausius in Britain, bringing the province back under Roman control, but the initial stability of the empire offered by Diocletian and the Tetrarchy was beginning to splinter. Constantius was elevated to the role of Augustus, or senior emperor, in a ceremony before the armies at Mediolanum (Milan) on 1st May AD 305. However, maneuvering by the other Tetrarchs, especially Galerius, blocked Constantine’s attempts to be recognized as his father’s junior partner. Constantine was able to escape the court of Galerius in the east and traveled west to be with his father, whose health was, by this point, ailing. Later in AD 305, father and son crossed from their imperial capital in Gaul to Britain to pursue a campaign against the Picts in the north of the island. Although they were victorious, claiming the title of Britannicus Maximus in early AD 306, Constantius was nearing his end. In the summer of that year, Constantine died in the city of Eboracum (York), much as Septimius Severus had almost a century earlier. So far removed from the Tetrarchs and their schemes, Constantine was proclaimed emperor by the soldiers under his control. The young man was now locked on a collision course with his imperial rivals.


2. Understanding Imperial Rivalries, Part 1: Constantine And The Tetrarchs

fragment of togate statue diocletian
Fragment of a togate statue of the emperor Diocletian, c. AD 295-300, J. P. Getty Museum


The position of the emperor to which Constantine’s soldiers elevated him to in AD 306 was in a number of ways vastly different to that which had first been envisaged by Augustus slightly over three hundred years earlier. Almost a century of crisis between the death of Alexander Severus in AD 235 and the accession of Diocletian in AD 284 had prompted the latter to consider how best to face the challenges that now faced the empire. The solution he had alighted upon was the division of authority into a system called the Tetrarchy. Diocletian ruled first with another co-emperor (an Augustus), and later, this was further devolved into a system of four emperors: two senior Augusti and two junior Caesars. Ostensibly, the Tetrarchy was a college of emperors, where although each member was of equal authority and enjoyed a division of power and resources, they also had an area of the empire over which they were the effective sovereign; originally, for example, Diocletian had ruled the eastern half of the empire from Nicomedia, with Galerius as his Caesar. Nevertheless, the ideology of Tetrarchy was typified by collegiality, as best exemplified by the famous porphyry statue group of the four Tetrachs – Diocletian and Maximian, the Augusti, and Galerius and Constantius, the Caesars – in Venice.  

four tetrarchs detail st marks
Detail of the Portrait of the Four Tetrarchs, photo by Carol Madge, taken from Constantinople in 1204 and now integrated into the Treasury of St Marks in Venice


The cohesion of the Tetrarchs ended with the death of Constantius and Constantine’s recognition as emperor by the soldiers now under his control. This effectively made him a usurper: according to the Tetrarchic system, with his father and Galerius as Augusti, power should have passed to Valerius Severus and Maximinus Daia, the nominated successors, respectively. The die however, had been cast, and dynastic credentials had proved decisive: to renounce power would have been a death sentence for Constantine. Constantine was forced to communicate the situation with Galerius, alleging his innocence in proceedings but also asserting his position. Galerius received Constantine’s message – a portrait of the young man in the robes of an Augustus – in a terrible fury. A compromise was reached, however, in the hopes of averting war; Constantine was recognized as Caesar. His “share” of the empire included the north and west, encompassing Britain, Gaul, and Spain, with control of the formidable Rhine armies too. He was quickly involved in repelling Frankish incursions in Gaul further consolidating his reputation as a leader. By now, however, the whiff of Constantine’s initial illegitimacy, lingering around the nature of his elevation by the soldiers, had reached Rome…


3. Maxentius And The Milvian Bridge: Divine Intervention?

copper nummus maxentius
A copper nummus of Maxentius, with a reverse depiction of the Temple of Roma with the goddess enthroned, and the legend Conservatores Urb Suae (Preserver of her city), struck at Ticinum, AD 307, Münzkabinett, Vienna


In Rome, another Tetrarchic son, overlooked, was growing envious of Constantine’s elevation. Maxentius, the son of Maximian (Diocletian’s first imperial partner) had cast scorn upon the imperial portrait of Constantine distributed in Rome and lamented his own poor fortune. Maxentius seized power for himself, taking control of Rome as emperor in October AD 306. The senior Tetrarch, Galerius, refused to recognize the usurper. He attempted to use the western Augustus (i.e. the senior of Constantine), Severus, to bring Maxentius to heel. However, the soldiers Severus led had once been under the command of Maximian; in a pattern so often repeated in Roman history, the soldiers defected to a recognized leader, changing their allegiance, and seized Severus. A hasty alliance was patched up between Maximian, brought out of retirement, and Constantine, with the former offering the young man his daughter Fausta as a bride. His acceptance and their marriage in AD 307 confirmed Constantine as the Augustus in the west. A council called by Galerius in 308 at Carnuntum (in modern Austria) aimed at resolving the tensions in Italy by forcing the abdication of Maximian again, as well as the demotion of Constantine back to Caesar. In their place, Licinius would be elevated to Augustus in the west. The endless machinations, promotions, demotions, and usurpations created a twisted web of resentments and loyalties which led to the disintegration of the Tetrarchic system, a crisis not helped by the death of Galerius in 311.

battle of the milvian bridge
Battle of the Milvian Bridge, Pieter Lastman, 1613, Kunsthalle Bremen


Maximian was the first to break ranks, rebelling against Constantine in AD 310. Leading a detachment of Constantine’s army, he attempted to spread the rumor that he had died and assume the imperial purple for himself. The troops, however, remained loyal. A desperate Maximian fled from Constantine, who was marching against him to resolve this uprising. Attempting to shelter in the city of Massilia (modern Marseille), the citizens opened the city gates to Constantine. Maximian was captured, and although Constantine made a show of clemency, Maximian was compelled to end his life: he hanged himself in July AD 310. Tensions naturally escalated between Maxentius, Maximian’s son, and Constantine, with the former presenting himself as a devoted son and the latter finding a new imperial lineage, aligning his dynasty with that of Claudius II Gothicus, one of the more successful third century emperors. Maxentius declared war on Constantine, prompting the latter to arrange an alliance with Licinius, who asserted his control over the eastern empire. Maxentius, based out of the heart of the empire in Rome, awaited the arrival of Constantine and his armies.



triumphant entry of constantine into rome
Triumphant Entry of Constantine into Rome, Peter Paul Rubens, c. 1621, Indianapolis Museum of Art


By AD 312, Constantine had crossed into Italy and was marching rapidly on Rome. Attempts to halt his progress, such as Augusta Taurinorum (Turin) and Brixia (Brescia), were quashed easily, and nor could more wily resistance at Aquileia or Ravenna hinder his progress. All the while, Maxentius sheltered in Rome and prepared for siege war; the city was, after all, by this time well defended by the vast walls erected by the emperor Aurelian some decades earlier. This type of warfare was not well received by the Romans, who reputedly mocked Maxentius openly at chariot races in October 312. Nevertheless, he still massively outnumbered Constantine, so when they drew up at the Milvian Bridge, to the north of the city, he may have felt confident: his mood was likely brightened by the prophecy of the Sibylline Books which asserted that on this day, “the enemy of the Romans should perish”. The battle that followed is famous not only for Constantine’s total victory over Maxentius, but also his decision to have the Greek letters Chi and Rho, initials symbolizing Christ, emblazoned on his soldier’s shields following an apparent vision from heaven, which revealed to him the prophecy: by this sign, conquer (in hoc signo, vinces), as recorded by Eusebius’ Vita Constantini, 1.28. This epiphany represents a crucial moment in the history of Christianity.


4. Restoring Rome: Confronting The Ghosts Of Emperors Past

the basilica of constantine
The Basilica of Constantine, Giovanni Battista Piranesi, c. 1757, Metropolitan Museum of Art, NY


With the defeat of Maxentius, drowned in the waters of the Tiber, Constantine entered Rome on 29th October AD 312. His entry into the imperial capital, the seat of empire, was marked by a grandiose adventus, an entrance ceremony, but the new ruler also neglected to make traditional sacrifices at the Capitoline Temple of Jupiter. There could be no surer indication that attitudes were beginning to change, to Rome and to its traditions. Nevertheless, much of what Constantine did in Rome was typical. This included effacing the memory of his former rival, whose corpse had been recovered from the Tiber and decapitated, from the city. His images were targeted for destruction, and he was roundly criticized by writers as a tyrant (in stark contrast to Constantine, the liberator). Around the city, structures built by Maxentius were dedicated to the new ruler, including the Temple of Romulus in the Forum (dedicated to Maxentius’ son, Valerius Romulus, not the mythical founder), and the colossal Basilica of Maxentius (now sometimes tellingly known as the Basilica Nova, the new Basilica), the largest single structure in the Forum.


arch of constantine
Arch of Constantine, adjacent to the Flavian Amphitheatre, AD 315, photo by the author


Perhaps the most striking monument to Constantine, however, is the triumphal Arch of Constantine adjacent to the Colosseum. Dedicated in 316, this monument was built to commemorate both the triumph over Maxentius, as well as his decennalia, the ten-year anniversary of his initial elevation. It was awarded to Emperor Constantine by the senate and it spanned the traditional triumphal route, the Via triumphalis. However, in its aesthetics, the arch is commonly associated with the advent of late antique artistic styles and practices.  The arch comprises an array of relief sculptures, some contemporary, but many of which have been taken from earlier imperial monuments and refashioned; likenesses of Trajan, Hadrian, and Marcus Aurelius, have been re-carved to portray Constantine himself. This utilization of reused material, commonly called spolia, has been the subject of much scholarly debate, with no consensus reached as to whether the practice was motivated by pragmatic concerns of cost and availability of materials, or whether one was meant to read this as an ideological contrivance: was the viewer meant to recognize the re-use and see Constantine as a new optimus princeps?


5. Understanding Imperial Rivalries, Part 2: Constantine And Licinius

gold aureus licinius i jupiter conservator
Gold aureus of Licinius I, with reverse depiction of Jupiter Conservator, struck in Nicomedia, AD 321-2, British Museum


As the master of Rome, Constantine could now look to consolidate his authority. This meant solidifying his relationship with Licinius, the ruler in the East. They met at Mediolanum in AD 313, where an alliance was solidified by the marriage of Licinius to Constantia, the half-sister of Constantine. Significantly, this meeting was where the Edict of Milan was agreed, granting official tolerance to Christianity, and a world away from the persecution of the earlier Tetrarchs. Tolerance of Christianity had already been indicated by Constantine’s donation of the Lateran Palace to the Bishop of Rome. Celebrations of unity were interrupted by news of Maximinus Daia’s insurrection in the east. Licinius departed at haste, defeated Maximinus, and left the empire now finely poised, between the control of two men.


constantine basilica s giovanni laterano
Constantine the Great Commissions the Building of the Basilica of S. Giovanni in Laterano, Guiseppe Belloni, 1656-1685, Museum Kunstpalast, Düsseldorf


The relationship could not be sustained however, and tensions escalated between Constantine and Licinius until violence became inevitable, with Licinius even having his rival’s statues destroyed in some towns. A battle at Cibalae followed in around 315, and another at Mardia in 317. A temporary settlement was reached whereby their sons (Crispus and Constantius, and Licinianus) were made Caesars, in a sense restoring the Tetrarchic system. It appears that Licinius soon after reneged on the notion of religious toleration. This was likely not motivated by his faith, but rather by the political realities: the Christians were seemingly a force for Constantine. A civil war erupted from these tensions in AD 324. Constantine, marching under the distinctly Christian icon of the labarum, defeated Licinius and his allies first at Adrianople, then at the Hellespont and Chrysopolis. Constantine initially spared his former ally, allowing him to live as a private citizen in Thessalonica. However, in 325, he accused Licinius of plotting against him and had him killed (along with his son, Constantine’s nephew!). Constantine was now master of the Roman world


6. Helena: Mother, Pilgrim, Saint

statue of empress helena
Seated statue of Empress Helena, earlier 2nd century AD statue with a recurved face, Musei Capitolini


Constantine was not the only formidable, nor significant, member of his family. Whilst his father had also left an indelible stamp on the history of the empire, there is a case to make for his mother – the empress Flavia Julia Helena, being an even more significant figure in history. She had been born to aristocratic parents in Asia Minor, perhaps the city of Drepanum (renamed Helenopolis after her death) in around AD 247. Helena outlived her husband and was a prominent figure in the public representation of Constantine’s dynastic legitimacy, receiving the title of Augusta in AD 325, but a major figure of the imperial court from the time of Constantine’s victories in 312. It is not for politics that she is so famous however, but for her faith. Helena was an early and significant adherent of Christianity and is most well known for her pilgrimage to the Holy Land and her acquisition of a number of relics that were brought back to Rome.



saint helena with cross lucas cranach
Saint Helena with the Cross, Lucas Cranach the Elder, 1525, Cincinnati Art Museum


As Augusta, Helena had been given access to the imperial treasury to locate relics of the Christian faith. Between 326 and 328 she journeyed to Palestine to find them. She was responsible there for establishing and embellishing a number of churches, including the Church of the Nativity in Bethlehem, the site of Christ’s birth. In Jerusalem, Helena reputedly had the Hadrianic Temple of Venus pulled down (it had been built on the site of the former Jewish Temple). It was also here that, as legend has it, the empress discovered fragments of the true cross, on which the Church of the Holy Sepulchre was built. Upon her return to Rome, the Basilica di Santa Croce in Gerusalemme was consecrated to house these relics. Helena died in AD 330 and was buried in a grand mausoleum o the Via Labicana outside of the city. Her alleged sarcophagus, a vast imperial porphyry edifice in its own right, is displayed in the Vatican museum. Helena was canonized, with her feast day being celebrated on 18th August by Catholics.


7. Building At Byzantium: Constantinople And A New Imperial Capital

constantine depicting constantinople mary and christ
Constantine depicting the city of Constantinople to the enthroned Mary and Christ, detail of the vestibule mosaic, 10th century, Hagia Sophia, Istanbul


Emperor Constantine’s defeat of Licinius did not just symbolize the quashing of a rival in civil war, but because of the religious and cultural undertones that had increasingly emerged, it represented the defeat of one power bloc by another. There was thus a need to re-integrate and reunite the empire. The establishment of a new imperial capital, Constantinople, on the site of the city of Byzantium on the Bosporus, provided not only the opportunity to reunite a fractured empire but also a canvas onto which a new ideology of empire could be mapped, free of the associations and pressures of Rome. Dedicated and renamed on 11th May 330, and allegedly picked over other sites such as Serdica, Sirmium, and Thessalonica, the former city of Byzantium had previously been the subject of imperial destruction and reconstruction in the Severan period, by Septimius Severus and Caracalla respectively, over a century earlier. The city’s exceptional strategic strength had been demonstrated previously, holding out against the siege of Septimius Severus for over a year! 



silver coin constantine
A silver coin with obverse portrait of Constantine; with a reverse depiction of the Tyche (fortune) of Constantinople enthroned, struck at Constantinople, AD 330, Münzkabinett Berlin


Constantinople was significantly closer to the vital imperial frontiers, but it also offered Emperor Constantine the chance to design an imperial capital that was more attuned to the new beliefs of empire. The relationship between the emperor and his new capital was widely celebrated, especially in the visual arts. Although the Christian faith had a prominent role to fulfill in the organization of the spaces of the new imperial capital and the buildings erected, the specter of Rome proved hard to evade. Many of the buildings erected to beautify the city and provide for the citizens there were distinctly Roman in character. These included the vast thermae, the Baths of Zeuxippos, the Hippodrome for chariot-racing (with room for around 80,000 spectators), and even a Forum of Constantine. The centrality of the new city was confirmed by the Million; this marker was the starting point for measuring distances around the empire, a clear rival to the miliarium aureum, or golden milestone, in the Forum at Rome. Constantine’s new capital was also ringed with an extensive series of defensive walls, confirming its new status.


8. Emperor Constantine The Great: Securing The Future

emperor constantine medallion
A gold medallion of Constantine I, with Constantine (centre) crowned by the manus Dei (hand of God), his eldest son, Constantine II, is to the right, whilst Constans and Constantius II are to his left, from the Szilágysomlyo Treasure, Hungary, photo by Burkhard Mücke,


With a new capital and his control of the empire now cleared of any rivals, you would be forgiven for thinking that Constantine would be able to rest easy. The reality was markedly different. Tensions appear to have erupted in the Constantinian household once more by AD 326. Sources are reticent to provide insight as to the emperor’s motivations, but in the spring of this year, he ordered the death of his wife, the Empress Fausta (daughter of Maximian), and his eldest son, Crispus. The latter was killed by poison, whilst his mother was suffocated by steam in an over-heated bath. Rumors of an illicit relationship between the two seem unfounded, and their death appears instead to have been motivated by a desire to facilitate the smooth succession of power. Power instead would pass to his sons Constantine II, Constans, and Constantius II, the last of whom would be succeeded by Julian the Apostate in AD 360.


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Baptism of Constantine, Giovanni Antonio Galli (also known as Lo Spadarino), first half of the 16th century, Fondazione Musei Senesi, Siena, via Google Art Project


From his new capital, Emperor Constantine’s later years were characterized by consolidation. Campaigns were waged against the Goths, leading to the fortification of the Danubian frontier and Constantine taking the title Dacicus Maximus in AD 336. He had planned a campaign in the east against the Persians, but the campaign was called off in 337 when a sickness gripped the emperor in the spring. The emperor fell gravely ill in the Easter of 337, and he left Constantinople. Arriving on the shores of the Gulf of Nicomedia (modern Gulf of Izmit), he sought out the therapeutic effects of the thermal baths. However, realizing the end was near, he sought a speedy return to the capital. He never made it. Approaching the end, he requested a baptism, which was administered by Eusebius of Nicomedia. He died soon after on 22nd May 337. 


In the space of his 30-year reign, Emperor Constantine had wrought considerable change across the empire, riving it forward into a new, markedly different future. His legacy spans the vast expanses of an empire and its history, from York in the north to its new capital in Constantinople, from military usurper to sole-ruler, and from the specters of the emperors of the Classical past to the spiritual rigors of its Christian present. We can debate, perhaps, his greatness, but his impact remains incontestable.

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By Kieren JohnsPhD Classics & Ancient HistoryKieren is a UK-based independent researcher with a PhD in Classics and Ancient History. His thesis explore the representation of imperial status during the reigns of the Severan emperors. He is passionate about sharing his interest in the ancient world. He is currently writing his first book.