Rome in the Crisis of the Third Century

The Crisis of the Third Century is the name modern historians give the fifty years between the murder of the emperor Severus Alexander in 235 CE and the accession of Diocletian in 284 CE. Whole regions broke away under rival rulers, coinage lost its value, and Rome fought on the Rhine, the Danube, and the Euphrates. Reigns averaged under three years, and most emperors were killed by Roman soldiers, usually their own troops or officers.

Two pressures fed the crisis: disease and army pay. An epidemic swept the provinces between 165 and 180 CE, weakening the empire. Septimius Severus, who took power in the civil war of 193, raised army pay and, according to Cassius Dio, told his sons to keep the soldiers rich and scorn everyone else. His son Caracalla raised pay again and in 212 extended Roman citizenship to nearly all free inhabitants of the empire, widening the tax base. The result was an army that cost more than the treasury raised and knew it could choose emperors. Rome had no succession law, so a legion’s acclamation was as valid as any other route to power.

In 235 the Rhine army decided Severus Alexander, who had paid off Germanic raiders instead of fighting, was not worth keeping. They killed him at Mogontiacum, modern Mainz, and acclaimed an officer Maximinus Thrax as emperor. His taxes for the frontier wars provoked a revolt in Africa in 238, and within twelve months six men held or claimed the throne: Maximinus himself, the governor Gordian I and his son Gordian II, the senators Pupienus and Balbinus, and the thirteen-year-old Gordian III. Five were dead by year’s end, and Gordian III was the sole survivor.

In 251, Gothic forces killed Decius at Abritus in modern Bulgaria, the first emperor to die in battle against a foreign enemy. In 260, the Sasanian king Shapur I captured the emperor Valerian near Edessa and commemorated it on rock reliefs at Naqsh-e Rustam. A second epidemic ran through the empire from about 249 to 270. Cyprian, bishop of Carthage, described the dying in his city; the disease remains unidentified.

Provinces that Rome could not defend began defending themselves. Postumus governed Gaul, Britain, and Spain from 260; Queen Zenobia took Syria, Egypt, and much of Asia Minor. Aurelian recovered both by 274 and gave Rome its first walls in centuries. His coinage reform of 274 raised official values without restoring silver content and prices climbed steeply afterward. The crisis finally ended in 284, when Diocletian took power and brought stability to the empire during his 20-year rule.

The severity of the crisis remains contested, and the evidence is largely archaeological: a sharp fall in dated inscriptions after the 230s, hoards buried in Gaul and the Rhineland in the 260s, and the first town walls from Britain to the Balkans. The material supports two readings: empire-wide breakdown, or sharp decline in some western provinces with others untouched. Within a decade Diocletian ruled from Nicomedia in modern Turkey, his co-emperor Maximian from Milan, and their deputies Constantius and Galerius from Trier and Sirmium. Rome kept Aurelian’s walls and ceased to be the seat of government.

FURTHER READING

1. Ando, Clifford. Imperial Rome AD 193 to 284. Vol. 6. Edinburgh University Press, 2012.
2. De Blois, Lukas. “The Crisis Of The Third Century Ad. In The Roman Empire: A Modern Myth?” The Transformation of Economic Life under the Roman Empire: Proceedings of the Second Workshop of the International Network Impact of Empire (Roman Empire, c. 200 B.C. – A.D. 476), Nottingham, July 4-7, 2001, edited by Lukas De Blois And John Rich, Brill, 2002, pp. 204–17. JSTOR, http://www.jstor.org/stable/10.1163/j.ctv2gjwvt0.18. Accessed 26 July 2026.
3. Witschel, Christian. “Re-Evaluating the Roman West in the 3rd c. A.D.” Journal of Roman Archaeology 17 (2004): 251–281.
4. Sonnelitter, Karen, and Rohr, Matthew. “Reduced Almost to Extinction” the Antonine Plague and the Fall of the Roman Empire. Siena University, 2024, Siena University Honors Theses. Siena University. JSTOR, https://jstor.org/stable/community.41052440. Accessed 26 July 2026.