Crisis of the third century

Roman imperial dynasties
Crisis of the Third Century
Chronology
Barracks Emperors		235–284
Gordian dynasty		238–244
Valerian dynasty		253–261
Gallic Emperors		260–274
Illyrian Emperors		268–284
Caran dynasty		282–285
Britannic Emperors		286–297
Succession
Preceded by Severan dynasty		Followed by Diocletian and the Tetrarchy

The Crisis of the Third Century, also known as Military Anarchy or the Imperial Crisis (AD 235–284), was a period in which the Roman Empire nearly collapsed under the combined pressures of invasion, civil war, plague, and economic depression. The crisis began with the assassination of Emperor Severus Alexander by his own troops in 235, initiating a 50-year period in 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 the Italian-centered and independent Roman Empire, proper, between them. Later, Aurelian (270–275) reunited the empire; the crisis ended with the ascension and reforms of Diocletian in 284.

The crisis resulted in such profound changes in the empire's institutions, society, economic life and, eventually, religion, that it is increasingly seen by most historians as defining the transition between the historical periods of classical antiquity and late antiquity.

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