“The annals record no such massacre of a battle except one, at Cannae.” This was the verdict of Ammianus Marcellinus, the Latin historian of the later fourth century when his narrative confronted the annihilation of tens of thousands of Roman soldiers on the blood-soaked battleground at Adrianople in AD 378. Not even the emperor had escaped. Suffering a fate similar to that which had befallen Decius in the mid-third century, the emperor Valens fell in battle, his body never to be recovered amidst the carnage wrought by Rome’s enemies, the Ostrogoths and Visigoths. A desire for glory, and rumors of the enemy’s shortage of soldiers, had prompted Valens to rush to the site of the battle. His hubris would be fatal, severely weakening the empire, and leaving it in desperate need of a new emperor.
Such was the situation that the empire found itself in late 378. It was hardly the ideal moment for the smooth transition of imperial power. In January 379, the emperor Gratian, the nephew of the vanquished Valens, promoted Theodosius to Augustus’s position in the east. The first of his dynasty and the founder of a line with a tremendous influence on the later Roman empire’s course, history now looks back on Theodosius as one of the ‘Greats’. The question remains, what was it that earned Theodosius I, the last man to rule both the Western and Eastern Empires, this moniker? The life of this emperor is a story of two themes: religion and rebellion. It would be the endeavor of Theodosius’ time as emperor to bring both to heel.
1. A Man Made in the Military: Theodosius’ Early Career
Born in the mid-third century, likely around AD 346/7, Theodosius’ origins did not immediately suggest that his destiny lay in the imperial purple. Some of the more dubious sources from antiquity give this away. Although he was born in Spain, some of these narratives attempt to move his birthplace from central Spain to the city of Italica in the south (near modern Sevilla). This was the birthplace of the emperor Trajan, the optimus princeps, or best emperor, and the attempts to create a thinly veiled ideological link are easily identifiable. Nevertheless, his father was a successful senior officer in the army. Theodosius the Elder, sometimes labeled ‘Count,’ served in the empire’s northern provinces under the emperor Valentinan I. He rose to prominence in his being sent to Britain to restore order to the province in 368 after it had rebelled. For his successes in restoring Roman order, he was granted the title of comes rei militaris per Britanniarum, recognizing him as the commander of the British forces.
Theodosius the Elder had not been alone on his British expedition. His son, the future emperor, had accompanied him. His son was involved in later campaigns too. The elder Theodosius’ successful return from Britain led to his promotion to the position of magister equitum praesentalis by Valentinian. He would lead campaigns against the Alemmani (370-1), the Sarmatians in Illyria (372), and to Mauretania in North Africa in 373. While his father was attempting to restore order in Africa, Theodosius was left as commander in Illyricum as dux Moesiae Primae. Disaster struck the family in 375: Valentinian died suddenly, he seemed to be so angry at some Quadi envoys that he suffered a stroke in the middle of berating them! Theodosius the Elder was arrested quickly and executed at Carthage in 376. His military successes seemingly made him a potentially dangerous rival to the new emperors, Gratian, the senior Augustus, and Valentinian II.
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Theodosius briefly retired from military life, back to his Iberian homeland where he was married and his first son, Arcadius, was born. He would return to the empire’s frontlines in 378 when he was appointed magister equitum on the Danube frontier.
2. An Empire Divided: Theodosius the Eastern Emperor
The death of Valens amid the carnage and bloodshed on the fields at Adrianople left his successor in something of a lurch. Gratian was the eldest son of the emperor Valentinian I, under whom Theodosius the Elder had served with such distinction. Upon his accession to the rank of Augustus in AD 367, Gratian took command of the western half of the empire, while Valens ruled the east. He had been rushing to the east to help Valens when news reached him of the emperor’s death. Facing the reality that a single emperor would be unable to face the pressures of stabilizing the imperial frontiers across several fronts, Gratian appointed the magister equitum, Theodosius, as his colleague. The empire’s division into these spheres of influence had been utilized previously, notably with Diocletian and the Tetrarchy. There was some reconciliation, with Theodosius’ father deified as Divus Theodosius Pater, ‘the Divine Father, Theodosius.’
As the emperor in the east, Theodosius I ruled from Constantinople. The city had increasingly begun dislodging Rome as the fulcrum of the empire since Constantine made it his capital in AD 330. His time here was frequently interrupted by the spate of wars he fought to defend the empire. Nevertheless, he left a lasting impression on the imperial capital. Theodosius is most closely associated with the Column of Theodosius, a colossal honorific monument that was to take center stage in the new Forum of Theodosius. The carving out of commemorative spaces in the urban landscape was common to the Roman emperors, including the paragons of classical imperial power: Augustus and Trajan, whose respective forums dominated Rome’s center. The Column and Forum, spectacular as they must have been, paled in comparison to the colossal Theodosian Walls, however, along with the spectacular Golden Gate, the most magnificent of the many entrance ways into the city.
3. An Emperor at War, I: Theodosius, the Goths and Magnus Maximus
The reign of Theodosius I was marred by several wars, as well as the pressures of the Goths who had asserted their right to be taken seriously by events at Adrianople. Theodosius played a large part in bringing to an end the Gothic Wars, which had begun with the mass migrations of the Goths to the shores of the Danube, as they fled the Huns. The wars continued after the defeat at Adrianople to such a degree that it was only in 380 that Theodosius was actually able to enter Constantinople. The Goths were eventually settled in the Pannonian region of the empire. There, they would be left to their own devices – rather than integrated into the Roman state – but they would be expected to defend these crucial border territories. Both Gratian and Theodosius were involved in these negotiations. Still, the imperial capital splendor (the conference between the Roman and Gothic leaders took place in Constantinople and the respect Theodosius afforded their leaders helped bring the negotiations to a favorable conclusion.
Theodosius would soon be back at war. In Britain, the soldiers of Magnus Maximus had proclaimed him emperor. A distinguished soldier, having possibly served under the Elder Theodosius in the early 370’s, Magnus was responsible for the death of Gratian in 383. Defeated outside Paris, the deposed emperor had fled south only to be slain at Lyon. Magnus marched on, aiming to conquer Italy and overthrow Valentinian II, a mere boy at this point. Stalled on the battleground, Magnus was brought to the negotiation table by Ambrose, the Bishop of Milan. In 384, it was agreed that Magnus would be recognized as Augustus in the West. He would rule from the city of Treves (modern Trier), over a territory encompassing Britain, Gaul, Spain, and North Africa. The usurper proved an effective emperor and a strong defender of Christianity. However, his ambition led him into conflict with Theodosius.
Marching against Valentinian II again in 387, he drove the emperor out of Milan and to the court of Theodosius. Mobilized together, they retaliated and invaded the western territories. Defeats proved costly for Magnus, especially the Battle of Poetovio in 388. Magnus surrendered at the city of Aquileia, but his requests for mercy were ignored. He was executed and his memory condemned.
4. An Emperor at War, II: Eugenius and the Making of an Imperial Dynasty
The victory over Magnus Maximus would bring only temporary peace to the empire. The next crisis point of Theodosius’ reign arrived in the spring of 392. Then Valentinian II died in somewhat mysterious circumstances at Vienne. Found hanged in his chambers, it was rumored that this imperial suicide was part of a plot instigated by the magister militum Arbogast, with whom Valentinian had previously clashed. Theodosius was now the sole surviving adult emperor. Arbogast himself, due to his non-Roman background (he was a Frank), could not be proclaimed emperor. Instead, the role fell to Flavius Eugenius, a “teacher of rhetoric” according to Zosimus. Although Eugenius was ostensibly Christian, it appears that his reign led to some moves to re-integrate traditional Roman polytheism into the empire. This put him on a collision course with the staunchly Christian Theodosius.
The second son of Theodosius I, Honorius, was elevated to the role of Augustus in early 393. Now ruling with his two sons, a new political reality was emerging: the Theodosian dynasty now commanded the empire. Eugenius could not be allowed to continue as emperor. The decisive battle was fought in western Slovenia, at the Battle of the Frigidus River (now, the Vipava) in 394. Despite the inability of Theodosius’ army to achieve victory on the first day of the assault, the divine intervention appears to have helped them seize the initiative on the second attempt. The Bora, a sometimes devastatingly strong wind from the Adriatic Sea, is alleged to have whipped up and blown directly into Eugenius’ forces leaving them unable to mount a suitable defense. Poetic license by the chroniclers of this battle is highly likely here, but the weather certainly fed into the narratives of this battle being one pitching the true Christian faith against paganism; Rufinus even likened it in importance to Constantine’s victory at the Battle of the Milvian Bridge in 312. With their armies broken, Eugenius was captured and executed. Arbogast, the engineer of Eugenius’ rise, had managed to flee but committed suicide shortly after the defeat at Frigidus.
Amidst the bloodshed and the confirmation of Theodosian authority, a young Goth leader, Alaric, had been serving in Theodosius’ armies against Eugenius. His rise to prominence would come later, much to the detriment of Arcadius…
5. Saint: The Triumph of Christianity
The reputation of Theodosius I as a “Great” likely stemmed in part from his devotion to Christianity and his impact on the faith’s development in the Empire. His defense of Christian beliefs and practices have been seen as central to the legacy of his victory over Eugenius, even if it is perhaps going too far to suggest the war was justified on religious grounds. The Christianity that Theodosius defended, however, was far from a unified religion. Theological debates had surrounded the religion since the reign of Constantine, particularly in the tensions between the Nicene and Arian Christological debates. The Nicene Creed, that Jesus the Son was equal to and of one substance with the Father (rather than inferior, as in Arianism), had been established at the Council of Nicaea in 325, led by Constantine. This was confirmed again in February 380, with the so-called Edict of Thessalonica.
Issued by Theodosius I, Gratian, and Valentinian ii, this edict made Nicene Christianity the state religion of the Empire. It also condemned other creeds – such as Arianism – and made their persecution acceptable.
The Edict is preserved in the Codex Theodosianus, the great collection of Roman laws issued since 312 (i.e., under Christian emperors), which was compiled during the reigns of Theodosius II and Valentinian III. The Edict effectively led to the confirmation of Orthodoxy and coincided with the emperor’s baptism. Another beneficiary was Gregory of Nazianzus, who was appointed patriarch of Constantinople. Alongside this bolstering of Christianity, Theodosius also cracked down on pagan religious practices. A series of decrees issued between 389 and 391 effectively sounded the death knell of Paganism: temples were closed, the sacred fire at the Temple of Vesta in Rome was extinguished and the order of Vestal Virgins disbanded, and the many prominent pagan sites were attacked.
6. Sinner: The Massacre of Thessalonica
If the city of Thessalonica (modern Thessaloniki) lent its name to one of the crowning triumphs of Theodosius, it also became synonymous with the emperor at his lowest. The most infamous moment of Theodosius’ reign came at this northern Greek city in the year 390. The city’s population rioted in anger against the local garrison commander, Butheric, who was a Goth. Butheric had attracted the ire of the Thessaloniki citizens by arresting a charioteer. They responded by lynching the commander and rioting. A clear demonstration of imperial anger, a retaliation aimed at restoring imperial power, was decided on as the course of action by Theodosius. The citizens had gathered in the Hippodrome at Thessalonica, continuing to protest, when the imperial soldiers were let loose on the populace. Up to 7,000 people, including women and children, were slaughtered in the city in just three hours of brutal bloodletting.
The fifth-century theologian Theodoret provides one of the most evocative accounts of the events in his Historia ecclesiastica (5.17):
“The emperor was fired with anger when he heard the news, and unable to endure the rush of his passion… Multitudes were mowed down like ears of gain in harvest-tide.”
Although it is one of the defining features of Theodosius’ reign, an imperial nadir and a stain on his historical legacy, there continues to be much debate amongst historians as to whether the massacre at Thessalonica ever actually occurred. An absence of contemporary sources does not help in identifying what exactly happened. At the time of the massacre, the emperor was not in Thessalonica, or even in the eastern provinces of the empire; at the time, Theodosius’ court was based at Mediolanum (Milan). It, therefore, remains debatable as to the extent of the emperor’s involvement in the events that unfolded.
7. A Penitent Emperor: Theodosius and Ambrose of Milan
One of the main reasons for the Thessalonica massacre’s endurance in historical imagination is how it paved the way for a demonstration of a new hierarchy. In this new order of things, the emperor’s power was brought to the heel by the spiritual. The Bishop of Milan, Ambrose, a prominent though somewhat irksome figure from Theodosius’ court, was appalled by the events at Thessalonica. The Bishop admonished the emperor, banning him from receiving communion until he had repented for this great sin. The excommunication of any emperor, let alone the man responsible for establishing Christian Orthodoxy, was a potent demonstration of new power hierarchies in the Christian Roman Empire. This has been valorized in art throughout the centuries, with the image of a bearded bishop barring the mighty Roman emperor from the church, blocking the door, an evocative representation, though one that is ultimately likely a dramatic fiction.
Ambrose is said to have advised the emperor to do penance for his crimes of ordering (or at least not stopping) the massacre at Thessalonica. The emperor completed an eight-month penance and was only admitted back into communion on Christmas Day in 390 at Milan. The prostration of the emperor before God is evocatively captured by the account of Theodoret:
“lying prone upon the ground he uttered David’s cry, “My soul cleaves unto the dust”… He plucked out his hair; he smote his head; he besprinkled the ground with drops of tears and prayed for pardon.”
It should be noted that many of the acts to crack down on Paganism and to promote further Christianity appear to have occurred in the aftermath of the emperor’s penance. Ultimately, the events at Thessalonica are likely unknowable. The events are now quasi-mythological, viewed almost entirely through the prism of the later fifth century, unashamedly Christian writers, including Sozomen, Socrates of Constantinople, and Rufinus alongside Theodoret. Whatever the realities of the event, this mythologizing was important, creating a narrative of exemplary ecclesiastical action and imperial penance and piety.
8. Father of a Titan: Theodosius I And Galla Placidia
Theodosius died in February, in the year 395. Suffering from edema, he passed away in Milan, where a funeral was held featuring a panegyric delivered by Ambrose. The former emperor’s body was transferred to the imperial capital, where he was buried in November in the Church of the Holy Apostles. Although he may not have been recognized as a ‘Great’ yet, his reputation as a successful emperor was confirmed by his deification as divus Theodosius. Unfortunately for the emperor, his legacy was tarnished by the ineptitudes of his male heirs, Arcadius and Honorius. The two sons ruled the two halves of the empire, Arcadius the east and Honorius the west. Although it would endure until the end of the empire in the west in 476, this administrative division was not conducive to ongoing stability. Also, the problems the empire faced from external threats were exacerbated by the internal pressures of fraternal rivalry. Indeed, Honorius was emperor when Rome itself was sacked in 410; the first time the city had fallen in over 800 years!
Although Theodosius’ sons were not quite as impressive as their father, the same cannot be said for his daughter, Galla Placidia. Few figures in the later Roman empire’s history bestride the political landscape quite so prominently as Galla Placidia, the child of Theodosius’ second marriage. She was variously the wife of Ataluf, the King of the Visigoths, and later an empress, following her marriage to Constantius III, emperor in the west, in 421. She was also the mother, and an advisor, of an emperor: Valentinian III.
Alongside her political influence in the turbulent final decades of the western empire, Galla Placidia is perhaps most well known for the glorious public works she completed across the empire, including her restoration of the Basilica of Saint Paul Outside the Wall in Rome, and the Church of the Holy Sepulchre in Jerusalem. Her legacy is best preserved in her works at Ravenna. That, however, including the Mausoleum she built for herself, which is resplendent with some of the finest mosaics from the Roman past.
The Epitome de Caesaribus of Aurelius Victor ends with Theodosius I’s death and the passing of imperial power to his two sons. The author is of little doubt about the excellence of Theodosius as an emperor, made clear by the pointed and consistent comparisons made with Trajan. The reality was evidently rather more complex. Theodosius reigned in complicated times and his was a reign of tremendous pressures both internal and external. Control was established, but at the price of much blood spilled and the endurance of Theodosius’ political and military successes were ultimately fleeting. Nevertheless, Theodosius was responsible for the consolidation of Christianity within the Empire. Perhaps it was his faith that was the source of his greatness.