The Roman Empire in the Third Century CE



The Severi

The third century crisis

The third century recovery

Long term trends in the third century

Further study


The sequence of good emperors was brought to an end by the accession to power of Marcus Aurelius’ unworthy son, Commodus (reigned 180-192 CE). He immediately put an end to the interminable fighting on the Danube frontiers by making a treaty with the northern tribes which was widely regarded as a sell-out. On his return to Rome he soon alienated the senate and upper classes by his passion for gladiatorial combat (he even participated himself). He became more and more irrational and dangerous, and was eventually murdered by one of his mistresses.

Commodus’ murder plunged the empire into a second round of civil wars, more than a hundred years after the first. This time these lasted four years, not just one. The an the senate chose to replace Commodus, Pertinax (reigned 192-3), was a stern disciplinarian, and the Praetorian Guard soon killed him. They then put the succession up for auction; but as in 68-9 events had moved away from Rome. Frontier armies began marching on Rome, and civil war followed. It was not until 197 that Septimius Severus, the commander of the Danubian armies, had defeated his rivals and was firmly in power. Severus (reigned 193-211 CE) was a native of North Africa, and his wife was from Syria.

The Severi

On coming to power Severus discharged the entire Praetorian Guard, and recruited a new one from amongst his own legionaries, many of whom were not Italians. He purged the senate of those who had supported one or other of his rivals. He strengthened the army, raising the pay of the troops considerably (a pay rise for them was in fact long overdue), and he raised three new legions. He ordered all taxes, even from senatorial provinces, to be paid directly into the imperial treasury – the senate’s treasury effectively became little more than the municipal treasury for the city of Rome.

Septimius was succeeded by his two sons, Caracalla and Geta. Caracalla (his official name was Marcus Aurelius Severus Antoninus Augustus; “Caracalla” was a nickname he got from the rough military cloak he wore) soon got rid of his brother and reigned alone (211-217 CE).

Caracalla embarked on a major expedition to Parthia. Whilst on it he was murdered by his Praetorian Prefect, Macrinus, who took the purple. He was the first non-senator to do so. He was himself soon murdered, and power passed back to members of the Severan family, with two young men, Elagabalus (218-222) and Alexander Severus (222-237) holding the throne in succession. In both cases, real power lay with their mothers. Elagabalus was of Syrian descent, a priest of a local god whose exotic debaucheries scandalised even Rome. He was soon disposed of. Alexander Severus’s reign saw a measure of stability, and some successes against Rome’s enemies, especially in the east, However his lieutenants were unable to deal effectively with a major Germanic invasion across the Rhine and Danube, and this undermined support for him amongst the troops there. A general mutiny led to his murder, bringing an end to the Severan dynasty.

Politics under the Severi

By this time, power lay with the army: the senate was no more than a cipher which endorsed the will of the troops. However, the long peace of the second century had led to military units being stationed in permanent barracks for generations. Their loyalties had become regional: the troops of the Danubian legions, for example, identified with their own section of the army rather than with the army as a whole. they had little sympathy with the troops far way on the eastern frontier. This trend had actually already been apparent in the events of 68-9, but were far more entrenched now.

Furthermore, there is a sense of growing indiscipline amongst the troops, at all ranks. Two of the five emperors of the period were killed by their own men in the midst of campaigns, Caracalla by a group of senior officers, Alexander Severus in a general mutiny. The army may have been the seat of power, but it was an increasingly unstable one.

Provinces and frontiers under the Severi

Away from the frontiers, the provinces remained largely at peace, and the prosperity of the previous period mostly continued. One trend that was becoming apparent, however, was inflation, caused by regular rounds of official devaluations of the coinage. This was exacerbated by heavier taxation, to pay for the larger and more expensive army. This was becoming a major problem by the end of the period.

The long-term spread of Roman citizenship reached a conclusion in this period when the emperor Caracalla issued his famous edict granting citizenship to all free men within the Roman empire (212).

All the emperors devoted much attention to the frontiers of the empire, and spent much of their time there. Septimius had to shore up frontiers weakened during the civil wars. He fought a major war against the Parthians, and as usual scored some successes but achieved little. He spent the last three years waging a costly wear in northern Britain, where he died.

After Septimius Severus’ time, problems along the frontiers multiplied. Invasions became more frequent, and no emperor was for long able to take his ease in Rome. Some scholars believe that, during the long peace of the second century CE, population pressures within the barbarian world of Germany and central Europe, or some other dynamic, had built up to create an urge to migrate into lands under Roman rule. By the end of the Several period invasions across the Rhine and the Danube were becoming regular events.

At the same time, in the east, a development had taken place which posed another major threat to the empire. Between 222 and 227 CE a new Persian dynasty, the Sasanians, had overthrown the Parthian Arsacids. This replaced a weak, divided regime with a strong, aggressive one. The eastern frontier of the Roman empire was now under graver threat than ever before.

At the same time the plague which had first appeared under Antonius Pius continued to return from time to time, preventing the manpower of the Roman empire from recovering to pre-plague levels.

Conditions were now turning against the Roman empire.

The Third Century crisis

On the murder of Alexander Severus, the troops acclaimed Maximinus Thrax as the new emperor (reigned 237-8 CE). He 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 complex sequence of events brought a young boy, Gordian III (238-244), to the throne with the senate’s support.

Short-lived emperors

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 in magnificent style (according to tradition the city was founded in 753 BCE). 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 escalates

The mid-third century marks something of a watershed in the troubles of this period. 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 defenceless 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 proclaimed their commander as emperors, and 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 much of the population of Antioch, one of the greatest cities in the Roman empire, away captive – 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 organising the Roman defences. 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 principate of the early empire was effectively dead. Indeed, 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 Third Century Recovery

The seeds of recovery seem to have beeb 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 defences 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 manifested themselves in the third century crisis. Some of these were continuations of changes which had begun well before the period, but which accelerated during the crisis; others were new to the period.

The 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 militarised. Also, practices modelled 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 defence.

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.

The 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 mobilising 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, theatres and so on when the cities’ very survival was at stake; defence 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.

Click here for the history of the Later Roman Empire

Further study

Click here for the Rise and Fall of the Roman Empire in maps

Click here for a Timeline on Ancient Roman civilization

Articles on Ancient Rome:

The Rise of Rome

Government and Warfare under the Roman Republic

The History of the Early Roman Empire

Government and Warfare under the Roman Empire

The Society and Economy of Ancient Rome

The History of the Later Roman Empire

See also:


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

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

– of the World when ancient Roman civilization flourished


Click here for a short overview of the history of the ancient Middle East, showing the role the Roman empire played in that region.

Click here for sources and further reading on Ancient Rome

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