The Crisis of the Third Century, also known as Military Anarchy or the Imperial Crisis (235–284 AD), was a period in which the Roman Empire nearly collapsed under the combined pressures of barbarian invasions and migrations into the Roman territory, civil wars, peasant rebellions, political instability (with multiple usurpers competing for power), Roman reliance on (and growing influence of) barbarian mercenaries known as foederati and commanders nominally working for Rome (but increasingly independent), plague, debasement of currency, and economic depression.
The crisis began with the assassination of Emperor Severus Alexander by his own troops in 235. This initiated a 50-year period during which there were at least 26 claimants to the title of emperor, mostly prominent Roman army 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 independent Roman Empire proper. Later, Aurelian (270–275) reunited the empire. The crisis ended with the ascension of Diocletian and his implementation of reforms in 284.
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.
After the Roman Empire had been stabilized, once again, after the turmoil of the Year of the Five Emperors (193) in the reign of Septimius Severus, the later Severan dynasty lost more and more control.
The army required larger and larger bribes to remain loyal.[2] Septimius Severus raised the pay of legionaries, and gave substantial donativum to the troops.[3][4] The large and ongoing increase in military expenditure caused problems for all of his successors.[5] His son Caracalla raised the annual pay and lavished many benefits on the army in accordance with the advice of his father to keep their loyalty,[6][7][8] and considered dividing the Empire into eastern and western sectors with his brother Geta to reduce the conflict in their co-rule.[9]
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 Sassanid 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.[10] 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.[11] 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,[12] 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 Imperial wrath,[14] 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 Legio II Parthica, and subsequently Pupienus and Balbinus were murdered by the Praetorian Guard.
In the following years, numerous generals of the Roman army 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 Sassanids 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.[16] Further disruption arose in 251, when the Plague of Cyprian (possibly smallpox) broke out. This plague cause
