The Late Roman Empire

The late Roman Empire covers the period of Roman history from the 3rd century CE, through to the decline and fall of the Roman Empire in the West in the 5th century CE (the empire continued on for another thousand years in the East, as the Byzantine Empire).

For an overview of the whole of Roman history, go the article, The Roman Empire.

Crisis and Recovery

The situation for the Roman Empire had been getting more difficult under the Severan emperors (193-237 CE). This dynasty ended on the murder of the last of them, Alexander Severus, and the troops along the Danube frontier acclaimed Maximinus Thrax as the new emperor (reigned 237-8 CE).

Maximinus was a professional soldier of humble birth, with no time for senatorial aristocrats. He achieved some success against the Germans, but his hostile attitude to the senate led to a revolt against his rule, starting first in Africa then spreading to Italy. In what looks like a throw-back to the time of the republic, the senatorial faction triumphed, and in 238, a confused sequence of events brought a young boy, Gordian III (238-244), to the throne with the senate’s support.

Gordian’s regime won some success against the Persians, but the young emperor was killed in uncertain circumstances whilst with his eastern army.  His successor, Philip “the Arab” (reigned 244-9 CE), managed to shore up the eastern frontier and scored some successes in dealing with another Germanic invasion across the Danube; and in 248 he was able to celebrate the 1000th anniversary of Rome’s founding (according to tradition the city was founded in 753 BCE) in magnificent style. However, barbarian invasions and army mutinies sapped Philip’s authority. In 249 the distinguished senator Decius, in command of the Roman army in the Danube, was acclaimed emperor by his troops and marched on Italy. He defeated and killed Philip near Verona.

Decius (reigned 249-51) is famous for instigating the first official empire-wide persecution of the Christians. However, he was killed fighting against the Goths in the Danube region.

The Crisis

The mid-Third Century marks something of a watershed in the troubles of the empire. Up to now invasions from outside the borders and mutinies and insurrections within the Roman army had been growing more and more frequent. These problems had mostly affected the frontier areas, plus the strategically located northern Italy. Most of the inner parts of the empire, although they were experiencing heavy taxation, inflation and reoccurrences of the plague, were not directly affected by these troubles. From now on, this changes.

In 251 a major Persian invasion destroyed a Roman army. leaving a gaping hole in the eastern frontier. The Persians ravaged the defenseless province, sacking Antioch, one of the greatest cities of the empire. Barbarian incursions across the Danube continued, with one group crossing the sea to Asia Minor and causing great destruction there – including burning the temple of Artemis at Ephesus.

Roman armies on the Danube and Rhine continued to proclaim their commanders as emperors, and to march into northern Italy to dispose of the current incumbent. In 253 Valerian emerged as emperor, and during his reign (253-60) the empire reached its nadir.


In the west a barbarian army broke through the Rhine frontier and marched right through Gaul and into Spain before being turned back. The victorious Roman general, a commander called Postumus, was promptly hailed emperor by his troops. So far so usual; but instead of marching into northern Italy, he remained in Gaul and established a break-away empire covering Gaul, Spain and Britain.

Valerian himself, meanwhile, after instigating a second official persecution of the Christians, had headed east to patch up Roman power in that part of the world. There he met the greatest humiliation the Roman empire ever experienced: the emperor was captured by the Persian emperor Shapur, to live out his days as a servant in the Persian king’s palace. The eastern provinces were now as good as lost, and the Persians now inflicted massive destruction on the cities of Syria – including taking away captive much of the population of Antioch, one of the greatest cities in the Roman empire  – before turning back to their own territory. In an extraordinary turn of events, the king of the city of Palmyra, located on the border between the Persian and Roman empires, took on the responsibility for organizing the Roman defenses. Over the coming years he and his widow, Zenobia, would extend their rule over many of the eastern provinces.

Valerian’s son, Gallienus, succeeded to the throne as sole emperor (he had ruled with his father since the latter’s accession); but the unity of the Roman empire was shattered. His rule extended over a rump, of Italy, Africa, the Balkans and Greece. The western and eastern portions of the empire were on their own. the barbarian invasions continued: in 267 a group of Goths sacked Athens.

By 260 CE the Roman Empire looked on the point of expiring altogether – perhaps even had expired. But then something extraordinary began to happen: in the following decades the Roman Empire, against the odds, recovered.


The seeds of recovery seem to have been planted while Gallienus reigned as sole emperor (260-8). He withdrew a large number of troops – many of them cavalry, which from now on became much more important in the Roman army – and brigaded them together into a strong, mobile army, stationed in northern Italy. From here it was able to guard Italy against all comers, barbarian or usurper alike, and if need be to move up towards the crucial Danube frontier to plug any gaps in the Roman defenses there.

This powerful force was now the most potent source of military, and therefore political, power in the empire. Its senior officers were all long-term professional soldiers of Danubian origin. It seems that senators were kept well away from this force, part of a trend in these years for professional soldiers to hold senior commands as well as provincial governorships – which, in these times of deep trouble, had themselves become more or less military posts.


The high command of this army soon got rid of Gallienus and elevated one of their own, an experienced general named Claudius, as emperor (reigned 268-70). He inflicted a major defeat on invading barbarians of the Goth people, and received the nickname “Gothicus”. Claudius was succeeded by Aurelian (270-275), who reunited the empire under his rule, first by conquering Queen Zenobia of Palmyra, who had been the effective ruler of the eastern provinces, and then the Gallic regime of Postumus and his successors. He abandoned the province of Dacia as undefendable. Anxious for the safety of Rome itself, Aurelian had new walls built around the city.

Aurelian was succeeded by a series of emperors who had brief reigns, the most notable being  Probus (reigned 276-82), who drove back a major German invasion to beyond the Rhine, and Carus (282-3), who in a short reign embarked on a successful campaign against the Persians. Each contributed towards beating back the barbarians and consolidating the work of Aurelian.  Finally, the emperor Diocletian came to power (reigned 284-305), and it was under him that stability was properly restored.

Long Term Trends in the Third Century

Various long-term trends become clear in the Third Century Crisis, at least to the historian. Some of these are continuations of changes which had begun well before the period, but which accelerated during the crisis; others are new to the period.

Emperor, court and central administration

From the mid-Third century, emperors spent by far the majority of their time on the frontiers: this was particularly true of the the soldier-emperors who restored the empire’s borders, none of whom spent much time in Rome. Milan was for much of the time the effective capital of the empire, and at other times the emperors lived in military camps on campaign. The city of Rome would in fact never again be a main imperial residence.

As a result, the close ties between emperor and senate, taken for granted in the earlier Roman empire, were broken. This hastened the trend towards the displacement of senators from high commands and provincial governorships, which had begun as early as the Severi.

Their mobile lifestyle also freed the emperors from other older traditions, allowing them to develop new styles of rule. There had been a long-term trend going back to second century, of emperors living in larger and larger palace complexes and assuming a more monarchical style of rule; but in the later third century there was a clear acceleration which saw a significant change in court styles.

An unsurprising feature of the time was that the emperor’s staff became completely militarized. Also, practices modeled on Persian antecedents, and alien to the old Roman traditions, became a feature at court (probably under the emperor Aurelian). Ceremonials and titles became more elaborate, and the emperor became increasingly separated from other mortals – the custom was introduced for those approaching the throne to prostrate themselves. An imperial title which started to come to the fore at this time was dominus, “lord”, and person of the emperor began to be referred to as “sacred”.

The army

One of the foremost of these trends was that, from the time of Marcus Aurelius onwards, soldiers’ pay began to rise markedly, and the army began to expand in size. Both these trends accelerated markedly in the military crisis of the mid-third century.

At the same time, the organization and structure of the army changed very significantly. Already by Marcus’ time the legions, the backbone of the army in the early empire, had become too unwieldy to be often deployed as complete units; increasingly detachments were drawn from several legions and brigaded together into task forces. This became general practice as the third century wore on, with the result that legions were gradually broken up and new mobile field armies emerged as the linchpins of the empire’s defense.

In the later third century barbarians began to be drafted into the army in significant numbers, either as recruits within regular units or in “federated” units under their own leaders.

Provincial administration

The government of the provinces changed practically out of all recognition. The evidence for this period is scant, but it is clear that, in their attempts to stem the disasters afflicting the empire, third century emperors had little time for the practices of previous, more stable times. The old distinction between senatorial and imperial provinces was swept away, and, with a few exceptions, governorships were no longer in the hands of senators but of equestrians, often from military backgrounds: these were more adept at ruthlessly mobilizing the resources of their provinces to supply the war effort. The old partnership between provincial governors and city councils was a thing of the past: the governors’ tax collectors, now no longer cultivated Roman gentlemen but tough professional soldiers, came to the cities with their harsh demands (often not for money payments but, with the collapse of the coinage, for grain, salt, and other goods). These demands were backed by military threat.

This process was a part and parcel of the broader militarization of the administration, from top to bottom. Whereas in previous times governors had had small staffs drawn from the soldiery to help them in their administrative duties, in the third century these staffs expanded vastly and took over the entire administrative apparatus of the empire. Officials were now soldiers, wit the ranks, pay and rations of military rank.

Social trends

The damage done by the barbarians during these years was immense. Cities which for centuries had remained undefended now acquired stout walls. In the west in particular, these new walls only surrounded the central core of the city, so that later Roman cities look much smaller than their earlier selves in the archaeological record.

There was a virtual cessation of urban public building in third century as the old-style civic patronage practiced by the city elites now came to virtual halt. in the conditions of the third century it would simply have been out of the question to fund new baths, theaters and so on when the cities’ very survival was at stake; defense was the absolute priority. Also, another factor may have been at work. Already in late 2nd century there are signs of strain in the upkeep of the public building stock in several cities, due to the abundance of previous benefactions; adding to this stock may have been increasingly unwelcome.


After the crisis of the Third century, when the Roman empire was overrun by invasions from beyond its borders and looked as if it would break up, a succession of soldier-emperors restored a measure of unity and pushed the invaders back over the frontiers. The emperor Diocletian (reigned 284 to 305 CE), like his immediate predecessors, came from the Danubian provinces, and like them he had had a career as a professional soldier. Unlike them, he succeeded in remaining in power for twenty years, and so gave the Roman empire a much-needed period of peace and stability. How did he do this?

The Tetrarchy

Successful though the efforts of the soldier-emperors were in reuniting the empire, one of the basic problems besetting the Roman Empire in the third century persisted. This was that armies operating in their own theatre of war were tempted to acclaim their commander emperor, who would then march, not against Rome’s enemies, but on their rivals.

Diocletian set about dealing with this problem by dividing the empire into two parts, east and west, and, with himself based in the east, appointed a fellow emperor in the west. These two emperors each had a junior emperor to support them. The senior emperors had the title of Augustus, while the junior emperors had that of Caesar. The two Caesars were the designated heirs of the two Augusti. This emphasized the fact that anyone aiming for the throne from outside this charmed circle started from a position of blatant illegality.

This solution was the result of trial and error and emerged over a number of years.  It dew on many precedents from the past, in which emperors had appointed others, usually sons or close relatives, as co-emperors. Indeed, under Diocletian family relationships were created to underpin the arrangement by marriage alliances and adoptions between the co-emperors.

Modern scholars call this system of co-emperors the tetrarchy, or “rule of four”. There was never any doubt amongst contemporaries that Diocletian remained supreme amongst them. The arrangement gave almost twenty years of much needed stability to the empire.

None of these emperors now lived in Rome. Diocletian based himself largely in Nicomedia, in northwest Asia Minor; his western colleague Galerius, traveled around near the frontiers, with Milan or Trier, in Gaul, as his preferred headquarters. The Caesars went as and where they were needed.

The administration

Diocletian and has colleagues were able to bring some system to the chaotic administrative condition the empire had fallen into. With the collapse of the silver coinage, the army was now paid and supplied partly by requisitions. In the crisis conditions of the third century, this was bound to be haphazard and a source of great distress to local civilian populations. Diocletian made tax payments – in both money and kind – regular and predictable. This alleviated the suffering for civilians and made the administrative more efficient.

The better to deal with the immense burden of tax collection and other administrative duties which now fell to the provincial governors and their staffs, which in previous times had been the preserve of city councils, Diocletian progressively reduced the size of provinces. This of course increased the number of provinces (Britain, for example, now had four provinces instead of two), so co-ordinating provincial administration became an issue. He therefore grouped the provinces into administrative regions called diocese. These were supervised by senior officials called vicarii, who reported to the Praetorian Prefects (of which there were two, one for each of the Augusti).

The military responsibilities of governors was now handed to army commanders called duces (pl. of dux). From now on, for the first time in Roman history, military and administrative careers were separated (although civil servants were still officially viewed as military personnel, due to the militarization of the administration in the third century crisis; they wore military-style uniforms and had the rank and pay of soldiers,). This process of separation was not quite complete: it would have to await the reign of Constantine before officials of the topmost rung, the Praetorian Prefects, lost their military powers.

This new system of provincial government required a much greater number of officials to run it than in the early empire.

The army

In the past Diocletian was credited with vastly increasing the size of the army, but scholars now think that he oversaw no more than a modest expansion. He did create many new legions, but these were not the huge units of six thousand men of the early empire; they were about one thousand men strong, probably in line with the example of late third century emperors, under whom the old legions had been dispersed and considerably reduced in size.

Also in line with developments in the third century, field armies now formed a major element in imperial defenses. However, Diocletian seems to have strengthened frontier defenses, building military roads and forts, and strengthened natural barriers. The eastern frontier in particular received a great deal of attention, and would remain very heavily defended throughout the fourth century.

Social and religious legislation

The overriding need to pay for the defenses of the empire, and the expanded imperial administration which went with it, determined the nature of Diocletian’s social legislation. It was aimed at ordering society in such a way that it was as easy as possible to raise taxes from it.

Much of the legislation from Diocletian’s time onwards was aimed at preventing various social groups from moving from place to place, or from one line of work to another, thus keeping them as regular taxpayers. Peasants were prohibited from leaving the estates on which they lived and farmed; they were (in law, at least; reality was a different thing) tied to their estates, making them similar to the serfs of later medieval times. Some professions regarded as crucial to the smooth operation of the state, such as shippers, bakers and soldiers, were made hereditary. Town councillors, who still had a vital role to play in the collection of taxes from their communities, were not allowed to leave their positions. From being a highly privileged elite in the early empire this had become a harassed and, in some parts, even impoverished class now, being required to personally guarantee their towns’ taxes from their own pockets. To keep them in place they were forbidden to enter the civil service, the army or the church.

That similar laws were repeated again and again later in the fourth century, in a shriller and shriller manner, points to this legislation not being very effective. Notably, town councillors left their positions in a steady trickle to take up a career the civil service – highly desirable as it freed them from their tax obligations and potentially opened the way to high office, much improved status and substantial wealth.

Another piece of Diocletian’s legislation that even he realized was ineffective was his attempted to control prices of a range of goods. He had the relevant laws withdrawn after a few years.

Diocletian’s attempts to dragoon society into supporting the military effort attests to the greater tax take in the later Roman empire than in the early empire. With a larger army and administration, this was inevitable. In the past, scholars have concluded that from Diocletian’s time onwards there was a harsh regime which created a caste-like society consisting of an oppressed majority, its vitality sapped by an unproductive minority of officials, courtiers, landowners, soldiers and clergy. However, the archaeological evidence gives a more nuanced picture; in most places it suggests an economy not much less vigorous than that of the early empire. In the east, indeed, the fourth and fifth centuries seem to have been ones of economic expansion. The west’s economy was a great deal more fragile, and seems never to have recovered all the ground lost in the third century; but even here, for example in Africa, southern Spain and much of Italy, above all Rome itself, this period shows signs of a great deal of prosperity.

Diocletian initiated the last great persecution of Christians. This fits in with the ordered mind which seems to be apparent in his other policies: he wanted uniformity of belief as well as behavior.

The Fourth Century

The end of the Tetrarchy

In the final analysis, Diocletian’s system of co-emperors rested on consent. After Diocletian retired in 305, to allow the Caesars to become Augusti in an orderly fashion, the system almost immediately began to break down. The ambitions of one of the Caesars, in particular, ensured that this was the case by rebelling against the Augustus of the west, Maxentius. In 312 Constantine fought and won the battle of the Milvian bridge, just outside Rome, and so established himself as the Augustus in the west. By 324 he had defeated the Augustus of the east and made himself the sole emperor of the Roman world.


Constantine’s reign (from 312 in the west, from 324 in the whole empire, until his death in 337) is one of the pivotal periods in European, even world, history. This is for two reasons. First, he became a Christian, and from his time until the modern age almost all European rulers have followed him in this, enabling the Christian Church to dominate religion and culture to such an extent that Europe has for most of its history been synonymous with the term “Christendom”.

Secondly, he founded a new capital, Constantinople, which would remain the center of the Roman (or, as scholars call this phase, the Byzantine) empire for another thousand years. With its superb location and massive walls it would act as a strong defense against the advance of Muslim for all of that time.

The first Christian emperor

In the course of his struggles for power, Constantine was converted to Christianity, He would not actually be baptized into the Christian church until right at the end of his life, but this was a fairly common practice at the time.

Under Constantine, all persecution of the Christian church ceased, and Christianity became a legal religion. All subsequent Roman emperors except one, Julian “the Apostate” (reigned 361-3), would also be Christians.

Under Constantine and his successors, the Christian church began to receive official patronage. The Clergy were exempted from the duties and responsibilities of town councillors, and Constantine himself embarked on a major church building program. The bishops of the Christian church started their rise to become prominent figures in their own towns and cities.

However, Constantine soon found himself drawn into the internal disputes between different groups of Christians. The main controversies revolved around attempts to define the precise nature of Christ in relation to God on the one hand, and mankind on the other. Constantine tried to resolve these issues by calling councils of Bishops, which would be regular occurrences in the later Roman empire. The Council of Nicaea of  325 CE, over which he presided, was the first of these, and probably the most influential: it hammered out a position (that Christ is both man and God) to which most of the the bishops, drawn from all over the Roman world, could sign up to, and which has remained broadly the orthodox view of mainstream churches ever since.

Pagans were not persecuted by Constantine nor any of his immediate successors, and certainly in Constantine’s time and for some time afterwards Christianity remained a minority religion. However, Constantine initiated a church building program which would soon start to make the Christian religion a key part of the physical townscapes of the empire.

The founding of Constantinople

As we have seen, the later third century emperors were too busy campaigning on the frontiers to live in Rome for any long periods; and none of the emperors of the Tetrarchy made Rome their residence. Constantine’s foundation of Constantinople was therefore building on practice going back at least a generation.

Yet there was something different about this act. It was no ad-hoc choice of a city as a temporary headquarters, but the deliberate selection of a permanent, second, imperial capital for the enormous empire. This is seen in the way it deliberately mimicked the features of Rome itself, above all the installation of second senate, and the appointment of Prefect of the City to govern it, like the historic Prefect of Rome, the most senior (if not the most powerful) official since Augustus’ day.

Constantinople was in fact the ancient city of Byzantium, renamed, refurbished and much upgraded (hence the name of the empire it ruled, the Byzantine empire). From the start this was to be a Christian city; but it was also to be a well-defended one. It was located on land jutting out into the sea, with only one landward side. Stout walls (later rebuilt on a massive scale) surrounded the entire city; these were to prove impervious to attack for more than a thousand years (unless treachery was involved).

Constantine’s administrative and military policies

In his secular policies, Constantine mostly followed in the footsteps of Diocletian, though with some departures of his own. He consolidated Diocletian’s provincial arrangements by dividing the empire into three sectors, each one under a Praetorian Prefect. One was responsible for the west, Spain, Gaul and Britain; another for the central trunk, Africa, Italy and the Balkans, and the other for the Eastern provinces in Asia Minor, the Levant and Egypt. Their military responsibilities were taken away from them altogether and handed over to new officers, a magister militum, also one for each of the sectors. The Praetorian Prefects were left as the top civilian officials of the empire, viceroys of their respective sectors. This measure completed the separation of military and civilian offices in the empire.

One departure from Diocletian’s practice was to expand the senatorial order. He removed the obligation for senators to attend meetings of the senate, or even to live in Italy; and from now on most members of the order were high officials and generals who held senatorial rank as a social cache rather than a substantive position. But Constantine also appointed senators who were actual members of the Roman senate, and who came from old Roman senatorial families based in Rome, to governorships much more frequently than Diocletian had done. Later in the fourth century such senators would reach very high office indeed, as members of the emperors’ inner council and as Praetorian Prefects.

Perhaps this expansion of the senatorial order and appointment of senators was linked to his introduction of taxation for this group (as a sort of quid pro quo). Since this was by far the wealthiest class within Roman society, this would have greatly strengthened the imperial treasury. Indeed, perhaps, in turn, this new taxation (which also brought certain merchants into the taxable fold) was linked to the issuing a new gold coinage, the solidus, which began to put an end to the chronic and disabling inflation the empire had experienced for so long.

In the military sphere, Constantine seems to have placed more emphasis on field armies stationed behind the lines than Diocletian had done, who is noted for having strengthened the frontiers.

Constantine’s successors

The fourth century CE was certainly more stable for the Roman empire than the third century had been; even so, it fell a long way short of the stability and peace of the first and second centuries CE.

On Constantine’s death in 337, fighting between his sons left the empire divided between two of them, Constans in the west and Constantius II in the east. In 350 a usurper, Magnentius, rose against Constans and killed him; but he himself was defeated and killed by Constantius (353), who thus became sole emperor.

In 355 the commander on the Rhine frontier, Silvanus, rebelled, but was killed soon after; this event probably prompted Constantius to realize that ruling alone was not a practical proposition by this time. He appointed his cousin Julian as Caesar. In 361 Julian succeeded Constantius as Augustus, but lasted only two years, dying on his return from a disastrous invasion of Persia

Julian was the only emperor after the reign of Constantine who was not a Christian. He attempted to re-establish paganism as the official religion of the empire, but his reign was far too short for him to accomplish anything quite so radical.

With Julian’s death, the family of Constantine came to an end. The high command of the eastern army chose an officer called Jovian to succeed him (361-2), and then Valentinian (364-75), who chose his brother Valens to reign as co-emperor. Valens remained in the east while Valentinian took the west.

In 375 Valentian died, and his 16 year old son Gratian, took over control of the west.

Struggles within and without

It can be seen from the above that internal struggles were frequent; they had a serious impact on the empire’s efforts to repel invaders. In Constantine’s last years, hostilities broke out between Rome and the Sasanian empire. His son Constantius II inherited the war here, which was prolonged by his struggles with his brothers. The rebellion of the commander of the Rhine frontier, Silvanus (355), prompted Germanic tribes to invade, and had to be pushed back by Julian; meanwhile Constantius was dealing with invasions in the Danubian sector. Constantius then had to return to the east, where the Persians had again invaded. He managed to patch things up there temporarily.

In 363 Julian, now sole emperor, embarked on a Persian campaign of his own, invading deep into Persian territory as far as the capital, Ctesiphon. He was, however, unable to take it, and was forced to retreat. His successor, Jovian (361-2), concluded a peace with the Persians, which was generally considered humiliating for the Romans, but which in fact stabilized the eastern frontier for a long time to come (though fighting did break out here from time to time).


These later fourth century emperors broadly continued the policies of Diocletian and Constantine. All, except Julian “the Apostate” (360-3) were Christians, and Julians’ attempts to turn back the clock to paganism came to nothing. In fact, this period saw the Christian church become firmly embedded into the government and society of the Roman empire. At both a local and empire-wide level, Christian bishops rose to prominence, with famous bishops such as Ambrose of Milan having a major influence on policy, and within cities across the empire, bishops becoming central figures within their communities.

The growing wealth of local churches meant that bishops were now the prime source of patronage, with money now no longer devoted to the building and upkeep of temples and public baths, and the funding of games, but in the construction and maintenance of churches, which now came to dominate the townscapes of the empire, and in charity to the poor.

Monasticism became a major force within the Christian Church in the fourth century, starting in Egypt, then spreading around the eastern provinces.

The overriding need to pay for the defenses of the empire, and the expanded imperial administration which went with it, determined the nature of Diocletian and Constantine’s social legislation. It was aimed at ordering society in such a way that it was as easy as possible to raise taxes from it.

As in Diocletian and Constantine’s time, much legislation continued to be aimed at fixing social groups in place on a hereditary basis – peasants on their land, soldiers and traders in their professions, town councillors in their cities – so that tax collection could be more efficient. It is quite clear that this legislation was at best only partially successful.

The Fall of the Empire in the West

The co-emperors Valentinian and his brother Valens came to power as co-emperors in the wake of the Julian’s disastrous campaign in the East (364). Later Valentinian’s son, Gratian, joined them as a third co-emperor.

These emperors were constantly engaged in fighting on all frontiers, and on occasion also had to put down rebellions. In 378, however, Valens was defeated and killed by the Goths at the battle of Adrianople, and his army destroyed. This was an enormous shock to the Romans, and left a gapping hole in their defenses along the eastern Danube. The Goths were able to rampage at will through the Balkans as far as the walls of Constantinople.

Valen’s successor in the east, Theodosius the Great (reigned 378-95),  patched up the situation in the Danube region as best he could, settling the Goths on their own land within the empire so that they caused no more destruction.

A major civil war occurred in 383-5 in which Theodosius dealt with the usurper Magnus Maximus, who had taken control of most of the western provinces. This further weakened frontier defenses along the Rhine and the Danube.

The division of the Empire

In 395, Theodosius the Great died. He left each of his two sons in charge of one half of the empire – Honorius in the West, Arcadius on the East. 

With the hindsight of history it is clear that this was to be a major source of weakness in the years to come, at least for the western half. With a longer, more dangerous frontier to defend and a smaller tax base with which to pay for troops (the western provinces being significantly less wealthy than the eastern ones), the western Roman government was now left largely to its own devices.

In 401, the Visigoths moved out of their new Balkan homeland into Italy. They demanded land and gold from the western Roman government. The western Roman government pulled forces from the German frontier to reinforce its Italian defenses, and pushed the Visigoths back into the Balkans. However, the Visigoths continued to threaten Italy and make demands on the Roman government and the Romans were unable to return their frontier troops to their permanent bases.

In 402 the west Roman court had moved from Milan to Ravenna, a city surrounded by marshes, and easily defendable. In this period of great crisis, the young emperor of the West, Honorius, was too weak to impose strong leadership, and the court was a hotbed of intrigue and violent in-fighting. Predominant power at court was in the hands of a barbarian general called Stilicho, the commander-in-chief of the army. While he lived, he was successfully able to defend Italy.

The breaking of the Rhine frontier

On the German frontier, however, the reduction in troop numbers had disastrous consequences. In the winter of 406-7 several German tribes crossed the frozen river Rhine en masse and overwhelmed the Roman defenses there. Some German tribes, such as the Franks, settled in territory near the frontier. Others, like the Seubi and the Vandals, marched great distances across Roman territory, burning villas and towns on their way. They eventually settled hundreds of miles from their original homelands, in Spain.

About half the frontier units may have been destroyed in the years after 406, or otherwise ceased to exist. The surviving units were no longer based on the borders, but used to strengthen the mobile field armies, in Gaul and Italy. The anarchy of the years after 406 also caused a heavy loss of tax revenue, due to loss of territory and the devastation caused by the invaders.

The Sack of Rome

In 408 Stilicho and his loyal German bodyguard were massacred. German soldiers in the Roman army based in Italy fled to the Visigothic camp, just outside the borders of Italy. The Visigoths, under their leader Alaric, then marched on Rome, threatening to sack the city if they did not get the land and gold they demanded.

In this dire situation, Honorius’ ministers quarreled amongst themselves, and did nothing; in 410, Alaric lost patience and sacked Rome. The Visigoths did not actually inflict much damage: a few buildings were burnt, but the city as a whole did not suffer greatly. Nevertheless this event sent a shockwave right around the empire – the unthinkable had happened! Although Rome had not been the political capital of the empire for over a century, it was still the “Eternal City”, representing the heart and soul of the Roman Empire.

In the following years, the Visigoths left Italy and headed into Gaul, which had descended into chaos. They established themselves in Aquitaine, in western Gaul. 

The Loss of Britain

In 410 the hard-pressed Roman forces trying to re-establish order in Gaul faced yet another challenge when the general commanding the Roman garrison in Britain declared himself emperor, and led his troops across the Channel with the aim of driving out the barbarians and establishing his rule. He failed in both objectives, and within a few years had been defeated by forces loyal to the western Roman emperor.

The units brought over from Britain never returned to their point of origin, and were instead used to bolster the Roman forces in Gaul. The inhabitants of Britain were left to defend themselves as best they could. 

The Condition of Gaul

In Gaul, however, some degree of order was established in the years after 410. Roman forces continued to be effective; on most occasions when they met barbarian armies in battle, they were victorious. However, the Rhine frontier defenses were no longer operating effectively, and the Roman army was too weak to force the Germans back out of Roman territory. Instead, these tribes settled down in enclaves within the western Roman provinces. The Visigoths and Burgundians soon became Roman allies, agreeing to provide the Roman government with military service. 

The Loss of North Africa

The Seubi and Vandals in Spain remained hostile. In 418 the Visigoths, with the Romans’ blessing, invaded Spain and occupied a large part of it. This prompted a large part of the Vandals to cross over to North Africa. By 440 they had firmly established their rule over this wealthy region, and had built up a fleet and brought the islands of Sicily, Sardinia, Corsica and the Balearics under their control.

The Huns 

Within the lands now under the control of the various barbarian groups, the previous Roman administration apparently continued to function to some extent. Roman law continued to apply to the Roman populations, while the German tribesmen retained their own tribal customs. Some evidence suggests that the Roman landowners in these areas had to cede a third of their estates to the invaders – probably more than enough land for the newcomers, as they had come in comparatively small numbers.

The western Roman throne was occupied between 425 and 455 by a nonentity, Valentinian III. Real power lay with the  commander-in-chief, who, after the late 420s, was a very capable general called Aetius. While he lived, he mostly succeeded in keeping the barbarians in check in Gaul and Spain.

The Hun invasion

In the late 430s the Huns, by now living in Eastern Europe, became restless. They aimed to take advantage of the confusion in the empire to expand their power. In 451, under their leader Attila, the Huns marched west, planning on conquering the western provinces of the Roman empire. 

This was an event long expected – and much feared – by both Romans and Germans. In fact, at the hard-fought Battle of Chalons (451), Attila’s forces were defeated by a Roman-Visigothic army under Aetius’ command.

The Huns then briefly invaded northern Italy, quickly withdrawing again to the Balkans, though not before utterly destroying a major Roman city, Aquileia. Attila died soon afterwards, and as rival leaders quarreled amongst themselves, the Huns’ power subsided. Within a short time, they had been absorbed by neighboring peoples, and the fear of them became nothing but a memory.

The End of the Western Empire

Aetius, the general who had dominated the western Roman government for many years, was murdered in 455; a little later, the emperor Valentinian III, who although a nonentity, had at least been on the throne for 30 years, was assassinated. In the aftermath, marriage agreements that had been negotiated between the murdered emperor and the king of the Vandals were set aside, leading the angry Vandal king to lead an attack on the city of Rome.

The second sack

This second sack of Rome was much more destructive than the first. Temples, palaces and other public buildings were stripped of their gold and silver ornamentation, and shiploads if captives were carted off to North Africa as slaves. 

In the confusion that followed this disaster, a German general called Ricimer came to power. He was unable to dominate the stage in the way that Stilicho or Aetius had done, however, as power was by now too fragmented between competing players: apart form the different factions at the court in Ravenna, such external actors as the senators in Rome, barbarian kings, the (by now) semi-independent commanders of nominally Roman armies in Italy, Gaul and the Balkans, composed almost entirely of German troops, changing sides at will, and the eastern Roman emperor dabbling in western politics. Puppet emperors were tugged one way or another, all reigning for a few years at most, none able to accomplish anything of importance.

The last Roman emperor

After Ricimer’s death in 472, more confusion followed. Puppet emperors continued to follow each other in quick succession. Finally, in 476, a force of barbarian troops mutinied, and their leader, Odoacar, seized power. He decided to do without a puppet emperor, and so despatched the last one, the child Romulus Augustulus, into retirement.

Zeno, the emperor of the eastern Roman empire, recognized Odoacar as king of Italy, under his (nominal) authority. The Roman empire once again had only one emperor – though by now the empire in the west had effectively ceased to exist.

The Western Roman provinces

The western provinces of the Roman empire were now home to several barbarian kingdoms. Although some were nominally subject to the Roman government, all were in fact independent, and from time to time grabbed more land for themselves. The death of Ricimer in 472, and the confusion at the Roman court which followed, removed the last barrier to their expansion. The German kingdoms now pushed out their borders, so that between them they soon covered almost the whole area of what had been the Roman provinces in Gaul and Spain (Britain and North Africa were long lost to the empire). The western Roman government and its forces were too weak to resist them.


Nevertheless, at the time when the last emperor of the West, Romulus Augustulus, was deposed by Odoacar in 476, there was still some Roman territory left in Gaul, and a Roman army there to defend it. This was under the general Aegidius and, after 465, his son Syagrius. Since Odoacar had no ambitions to rule any territory outside Italy and adjacent portions of the Balkans, Syagrius’ territory effectively became an independent kingdom. Not for long: in 486 the Franks, under their king Clovis, defeated Syagrius’ forces at the battle of Soissons. They annexed the last of the Roman territory in Gaul to their own kingdom.


Odoacar’s Italian kingdom was now but one of several independent states in what had been the western Roman empire. And soon, like all the other kingdoms, Italy came under the rule of a German tribe, when the Ostrogoths occupied Italy in 488. Like Odoacar before him. the Ostrogothic king, Theodoric, ruled Italy in nominal subjection to the emperor in Constantinople.

The decline of Roman civilization in the West

In all these states, the German rulers governed their subject populations through Roman officials and administrative institutions. These helped to preserve Roman law and administrative practice for later ages: Roman law applied to the old Roman (that is, non-Germans) population, and German tribal customs for the conquerors.

The sophisticated way of life of the Romans could not be maintained in this long period of confusion and chaos, however. Trade shrunk significantly, as did the towns. The well-built roads gradually deteriorated. The beautiful villas of the countryside seem to have disappeared almost entirely, probably replaced by fortified wooden structures, the better to protect the estates’ owners and their dependents against attack. With the decline of rural and urban mansions went the well-stocked libraries of the cultured Roman elite. Literary culture became much more restricted, and it was left to the Christian church, and specifically the monasteries, which now dominated the spiritual and intellectual life of the people, to preserve what it could of the classical civilization. 

The towns came increasingly under the control of the bishops, who now stepped forward as the natural leaders of the community. These men towered above all other public figures in the eyes of the townsfolk. They were often members of leading Roman families who had exercised authority in the area for generations, educated and gifted as administrators and diplomats. By now most of the population were members of the Christian church who looked to their bishops for secular as well as spiritual leadership in these difficult times.

The East

As in the West, the emperors of the Eastern Empire during the 5th century CE were mostly nonentities, and under the control of powerful ministers. However, the imperial administration based in Constantinople continued to function smoothly and effectively, and the Eastern Empire remained intact throughout the whole period that the Western Empire was going through its death throes.

Since the division of the empire in 395, taxes collected in the East were spent in the East. As the eastern provinces were wealthier than the western ones, this meant that the eastern treasury was a great deal fuller. Apart from the Balkans, which saw heavy fighting, the eastern half of the empire suffered no major barbarian invasions. Above all, the eastern frontier with Persia remained mostly quiet. In contrast to the West, there had been little loss of tax revenue to the eastern Roman government in Constantinople. The rich lands of Asia Minor, Syria and Egypt remained untouched by external attack and were still prosperous.

Apart from maintaining the army at full strength, the imperial government in Constantinople was also able to bribe barbarians to keep away from its territories.

For the population as a whole, life in the Eastern Roman Empire went on much as before. There were many great cities which housed an intact civilization – albeit one that was increasingly moving away from its Classical roots. It was Christian rather than pagan, and was increasingly Greek, not Latin, in both language and culture. These features lead modern scholars to call it the Byzantine Empire, rather than the Roman Empire. This refers to fact that its capital, Constantinople, had once been called Byzantium.

The empire would last for more than a thousand years, until 1453, preserving much of the old Greek and Roman civilization. 


Further Study

TimeMaps Resources:

Articles on Ancient Rome and related topics:

The Civilization of Ancient Rome

History of the Early Roman Empire

Government and Warfare under the Roman Empire

The Society and Economy of Ancient Rome


Ancient Europe, showing the rise and fall of the Roman empire in the context of European history

The Middle East, showing the impact of the Roman empire on that region

The World when ancient Roman civilization flourished