The Crisis of the Third Century, also known as the Military Anarchy or the Imperial Crisis, was a period in Roman history during which the Roman Empire nearly collapsed under the combined pressure of repeated foreign invasions, civil wars and economic disintegration. At the height of the crisis, the Roman state split into three distinct and competing polities. The period is usually dated between the death of Severus Alexander (235) and accession of Diocletian (284). The crisis resulted in such profound changes that it marks the transition between the historical periods of classical antiquity and late antiquity.
The crisis began in 235 with the assassination of Emperor Severus Alexander by his own troops. During the following years, the empire saw barbarian invasions and migrations into Roman territory, civil wars, peasant rebellions and political instability, with multiple usurpers competing for power. This led to the debasement of currency and a breakdown in both trade networks and economic productivity, with the Plague of Cyprian contributing to the disorder. Roman armies became more reliant over time on the growing influence of the barbarian mercenaries known as foederati. Roman commanders in the field, although nominally loyal to the state, became increasingly independent of Rome's central authority.
During the crisis, there were at least 26 claimants to the title of emperor, mostly prominent Roman generals, who assumed imperial power over all or part of the empire. The same number of men became accepted by the Roman Senate as emperor during this period and so became legitimate emperors. By 268, the empire had split into three competing states: the Gallic Empire (including the Roman provinces of Gaul, Britannia and, briefly, Hispania); the Palmyrene Empire (including the eastern provinces of Syria Palaestina and Aegyptus); and, between them, the Italian-centered Roman Empire proper.
The reign of Aurelian (270–275) marked a turning point in the crisis period. Aurelian successfully reunited the empire by defeating the two breakaway states, and carried out a series of monetary reforms which helped restore some measure of stability to the Roman economy. The crisis is said to have ended with Diocletian's final victory against Carinus in 285 and his restructuring of the Roman imperial government, economy and military.
History
Following the death of Emperor Marcus Aurelius in 180, the long period of stability and prosperity in the Empire came to an end. Commodus, Marcus Aurelius's son and successor, had little interest in ruling and his reign was notably corrupt, ending with his assassination in 193. What followed was the Year of the Five Emperors, resulting in a power struggle that led Septimius Severus and Clodius Albinus to seize power as co-emperors. This was challenged by Pescennius Niger, leading to a civil war that saw Niger defeated, before Severus turned on and defeated Albinus in 197, after which Severus proclaimed himself sole emperor.
In order to maintain the loyalty of the armies, Severus raised the pay of legionaries, and gave substantial donatives to the troops. This policy was maintained by his successors in the Severan dynasty. Over time the army required larger and larger bribes to remain loyal. The large and ongoing increase in military expenditure caused problems for all of his successors. One of the outcomes of this was the growing influence of the office of Praetorian prefect; initially held by the leader of the Praetorian Guard, under the Severans the position grew to assume greater administrative and advisory duties. Emperor Severus Alexander made the post of prefect open to Senators during his reign, further expanding its influence.
Instead of warring in foreign lands, the Roman Empire was increasingly put on the defensive by marauding enemies and civil wars. This cut off the essential source of income gained from plundering enemy countries, while opening up the Roman countryside to economic devastation from looters both foreign and domestic. Frequent civil wars contributed to depletion of the army's manpower, and drafting replacement soldiers strained the labour force further. Fighting on multiple fronts, increasing size and pay of the army, increasing cost of transport, populist "bread and circuses" political campaigns, inefficient and corrupt tax collection, unorganised budgeting, and paying off foreign nations for peace all contributed to the financial crisis. The emperors responded by confiscating assets and supplies to combat the deficit.
The situation of the Roman Empire became dire in 235. Many Roman legions had been defeated during a previous campaign against Germanic peoples raiding across the borders, while the emperor Severus Alexander had been focused primarily on the dangers from the Sasanian Empire. Leading his troops personally, the emperor resorted to diplomacy and accepting tribute to pacify the Germanic chieftains quickly, rather than military conquest. According to Herodian, this cost Severus Alexander the respect of his troops, who may have felt that more severe punishment was required for the tribes that had intruded on Rome's territory. The troops assassinated Severus Alexander and proclaimed the new emperor to be Maximinus Thrax, commander of one of the legions present.
Maximinus was the first of the barracks emperors – rulers who were elevated by the troops without having any political experience, a supporting faction, distinguished ancestors, or a hereditary claim to the imperial throne. As their rule rested on military might and generalship, they operated as warlords reliant on the army to maintain power. Maximinus continued the campaigns in Germania but struggled to exert his authority over the whole empire. The Senate was displeased at having to accept a peasant as Emperor. This precipitated the chaotic Year of the Six Emperors during which all of the original claimants were killed: in 238 a revolt broke out in Africa led by Gordian I and Gordian II, which was soon supported by the Roman Senate, but this was quickly defeated with Gordian II killed and Gordian I committing suicide. The Senate, fearing the wrath of Maximinus, raised two of their own as co-Emperors, Pupienus and Balbinus, with Gordian I's grandson Gordian III as Caesar. Maximinus marched on Rome but was assassinated by his own troops, and subsequently Pupienus and Balbinus were murdered by the Praetorian Guard.
In the following years, numerous Roman generals fought each other for control of the empire and neglected their duties of defending it from invasion. There were frequent raids across the Rhine and Danube frontier by foreign tribes, including the Carpians, Goths, Vandals, and Alamanni, and attacks from the Sasanian Empire in the east. Climate changes and a sea level rise disrupted the agriculture of what is now the Low Countries, forcing tribes residing in the region to migrate into Roman lands. Further disruption arose in 251, when the Plague of Cyprian (possibly smallpox) broke out. This plague caused large-scale death, severely weakening the empire. The situation was worsened in 260 when the emperor Valerian was captured in battle by the Sasanians (he later died in captivity).
Throughout the period, numerous usurpers claimed the imperial throne. In the absence of a strong central authority, the empire broke into three competing states. The Roman provinces of Gaul, Britain, and Hispania broke off to form the Gallic Empire in 260. The eastern provinces of Syria, Palestine, and Aegyptus also became independent as the Palmyrene Empire in 267. The remaining provinces, centered on Italy, stayed under a single ruler but now faced threats on every side.
An invasion of Macedonia and Greece by Goths, who had been displaced from their lands on the Black Sea, was defeated by emperor Claudius II Gothicus at the Battle of Naissus in 268 or 269. Historians see this victory as the turning point of the crisis. In its aftermath, a series of tough, energetic barracks emperors were able to reassert central authority. Further victories by Claudius Gothicus drove back the Alamanni and recovered Hispania from the Gallic Empire. He died of the plague in 270 and was succeeded by Aurelian, who had commanded the cavalry at Naissus. Aurelian reigned (270–275) through the worst of the crisis, gradually restoring the empire. He defeated the Vandals, Goths, Palmyrene Empire, and finally the remainder of the Gallic Empire. By late 274, the Roman Empire had been reunited into a single entity. However, Aurelian was assassinated in 275, sparking a further series of competing emperors with short reigns. The situation did not stabilize until Diocletian, himself a barracks emperor, reunified the empire in 285.
More than a century would pass before Rome again lost military ascendancy over its external enemies. However, dozens of formerly thriving cities, especially in the Western Empire, had been ruined. Their populations dead or dispersed, these cities could not be rebuilt, due to the economic breakdown caused by constant warfare. The economy was also crippled by the breakdown in trading networks and the debasement of the currency. Major cities and towns, including Rome itself, had not needed fortifications for many centuries, but now surrounded themselves with thick walls.
Fundamental problems with the empire still remained. The right of imperial succession had never been clearly defined, which was a factor in the continuous civil wars as competing factions in the military, Senate, and other parties put forward their favored candidate for emperor. The sheer size of the empire, which had been an issue since the late Roman Republic three centuries earlier, continued to make it difficult for a single ruler to effectively counter multiple threats at the same time. These continuing problems were addressed by the radical reforms of Diocletian, who broke the cycle of usurpation. He began by sharing his rule with a colleague, then formally established the Tetrarchy of four co-emperors in 293. However the trend of civil war would continue after the abdication of Diocletian in the Civil wars of the Tetrarchy (306–324) until the rise of Constantine the Great as sole Emperor. The first Roman emperor Augustus, who had established the Pax Augusta ('Peace of Augustus') in the 1st century BC, had used the title princeps ('leading citizen'). Historians call this first phase of Roman imperial rule the Principate, as Augustus created a system of imperial government that maintained Republican norms and consent given by the Roman Senate. The Principate period ended with the Crisis of the Third Century and the reign of Diocletian, who discontinued the use of the princeps title; from his reign onward emperors used the title domini ('lords').
The crisis resulted in such profound changes in the empire's institutions, society, economic life, and religion that it is increasingly seen by most historians as defining the transition between the historical periods of classical antiquity and late antiquity. The empire survived until 476 in the West and until 1453 in the East.
Causes
Problem of succession and civil war
From the beginning of the Principate there were no clear rules for the imperial succession, largely because the empire maintained the facade of a republic.
During the early Principate, the process for becoming an emperor relied on a combination of proclamation by the Senate, popular approval, and acceptance by the army, in particular the Praetorian Guard. A family connection to a previous emperor was beneficial, but it did not determine the issue in the way a formal system of hereditary succession would. From the Julio-Claudian dynasty onwards there was sometimes tension between the Senate's preferred choice and the army. As the Senatorial class declined in political influence and more generals were recruited from the provinces, this tension increased.
Whenever the succession appeared uncertain, there was an incentive for any general with support of a sizable army to attempt to seize power, sparking civil war. The most recent example of this prior to the Crisis was the Year of the Five Emperors which resulted in the victory of Septimius Severus. After the overthrow of the Severan dynasty, for the rest of the 3rd century, Rome was ruled by a series of generals, coming into power through frequent civil wars which devastated the empire.
Natural disasters
The first and most immediately disastrous of the natural disasters that the Roman Empire faced during the Third Century was the plague. The 2nd-century Antonine Plague that preceded the Crisis of the Third Century sapped manpower from Roman armies and proved disastrous for the Roman economy. From 249 to 262, the Plague of Cyprian devastated the Roman Empire to such a degree that some cities, such as the city of Alexandria, experienced a 62% decline in population. These plagues greatly hindered the Roman Empire's ability to ward off barbarian invasions but also factored into problems such as famine, with many farms becoming abandoned and unproductive.
A second and longer-term natural disaster that took place during the third century was the increased variability of weather. Drier summers meant less agricultural productivity and more extreme weather events led to agricultural instability. This could also have contributed to the increased barbarian pressure on Roman borders, as they too would have experienced the detrimental effects of climate change and sought to push inward to more productive areas of the Mediterranean region.