Crisis of the Third Century
The Crisis of the Third Century brought the Roman Empire to the edge of extinction. In the year 235, a group of Roman soldiers murdered their own emperor, Severus Alexander, and handed the throne to a military commander named Maximinus Thrax, a man of such humble origins that the Senate refused to accept him. What followed was fifty years of relentless civil war, plague, foreign invasion, and economic collapse that fractured the empire into three competing states and left dozens of thriving cities in ruin.
How did the most powerful political entity the ancient world had ever produced nearly destroy itself from within? What combination of structural flaws, natural disasters, and catastrophic leadership failures pushed Rome past the point of recovery? And who, in the end, actually held the empire together long enough for someone else to rebuild it?
From the very beginning of what historians call the Principate, Rome had no clear rules for who became emperor next. The system rested on a fiction, that the empire was still a republic, and that fiction made a formal hereditary succession politically impossible to declare.
In practice, a new emperor needed proclamation by the Senate, popular approval, and acceptance by the army, particularly the Praetorian Guard. A family connection to the previous emperor helped, but it settled nothing. As the senatorial class declined in influence and military commands shifted to men recruited from the provinces, the tension between Senate and army grew sharper.
The result was a structural trap. Any general who commanded a large enough force had an incentive to reach for the purple whenever the throne appeared weak. The most recent warning before 235 had come in the Year of the Five Emperors, which ended with Septimius Severus consolidating power and buying army loyalty with raised legionary pay and large cash gifts called donatives. His successors in the Severan dynasty continued the practice, and over time the army demanded ever-larger bribes to stay loyal.
Severus Alexander, the last of that dynasty, tried a different approach when Germanic tribes raided across the border. Rather than launch a costly military campaign, he paid off the Germanic chieftains and accepted tribute. The historian Herodian records that this decision cost Severus Alexander the respect of his troops, who felt the tribes deserved punishment rather than payment. The soldiers assassinated him at Mogontiacum in Germania Superior and proclaimed Maximinus Thrax, commander of one of the legions, as emperor.
Maximinus Thrax was the first of what became known as the barracks emperors, men raised to power by the troops without political experience, distinguished ancestry, or any hereditary claim. His rule rested entirely on military force, and the Senate, outraged at having to accept what they called a peasant as emperor, refused to cooperate.
In 238 alone, six men held or claimed the title of emperor. A revolt broke out in Africa led by Gordian I and his son Gordian II, which the Senate quickly endorsed. Gordian II was killed fighting a pro-Maximinus army led by Capelianus, and his father committed suicide immediately after. The Senate then elevated two of their own, the 74-year-old Pupienus and the 60-year-old Balbinus, as joint emperors, with Gordian I's grandson, Gordian III, designated as Caesar. Maximinus marched on Rome but was assassinated by his own troops. Pupienus and Balbinus, having survived barely 99 days in office, were then murdered by the Praetorian Guard.
The pattern that followed was relentless. The source records over fifty people claiming the title of augustus during the crisis period, with only about half ever receiving recognition from the Roman Senate. Nearly every single one of these legitimate emperors died violently, most killed by their own troops.
The low point came in 260 when the emperor Valerian was captured in battle by the Sassanid Persians at the Battle of Edessa, an event the source describes as an unprecedented disaster in Roman military history. He later died in captivity. With the emperor gone, the provinces of Gaul, Britain, and Hispania broke away to form the Gallic Empire in 260, while the eastern provinces of Syria, Palestine, and Egypt became independent as the Palmyrene Empire in 267.
The soldiers killing each other were not acting in a vacuum. Natural forces were compounding every political failure simultaneously.
The Antonine Plague of the second century had already drained manpower from Roman armies before the Crisis began. Then, from 249 to 262, the Plague of Cyprian, possibly smallpox, tore through the empire with staggering force. The city of Alexandria experienced a 62% decline in population during this period. Farms were abandoned, famine spread, and the army's ability to resist barbarian raids weakened at precisely the moment it most needed to hold firm.
Longer-term climate shifts added a second layer of pressure. Drier summers reduced agricultural output across the Mediterranean, and increased weather variability disrupted farming at scale. These same climate changes pushed barbarian groups on Rome's frontiers into motion, not merely as raiders seeking plunder, but as peoples whose own food supplies had become unreliable. The tribes that coalesced into the Alamanni and the Franks, the Gothic groups displaced from their territories on the Black Sea, the Carpians and Vandals crossing the Rhine and Danube, all were partly products of an ecological crisis that Roman policy was never designed to address.
Frequent civil wars depleted the army's manpower further, and the drafting of replacements strained the labour force at exactly the moment farming most needed workers. Rome was simultaneously losing soldiers and losing the people needed to feed them.
Septimius Severus had enlarged the army by one quarter and doubled the base pay of legionaries. Every short-lived emperor who followed needed to pay an accession bonus to secure loyalty, and the fastest way to raise that money was to debase the coinage, mixing less and less silver into the denarius.
The denarius had served Rome for 300 years. By the time Diocletian came to power it had nearly collapsed, and trade was being carried out without retail coinage at all. The old equivalencies, 1 pound of gold equal to 40 gold aurei equal to 1,000 denarii equal to 4,000 sestertii, had become meaningless fiction. Real values shifted to gold or were notional, figured in bullion or bronze.
The historian Henry St. Lawrence Beaufort Moss describes the pre-crisis trade network in vivid terms: merchants could travel from one end of the empire to the other within weeks, moving grain from North Africa, Egypt, and the Danube Valley; metals from Western Europe; wine and oil from Provence and Aquitaine; timber, pitch, and wax from South Russia and Anatolia. This was an integrated Mediterranean economy of a scale, Moss writes, not repeated until a few centuries before his own time.
Civil unrest made those trade routes dangerous. Debased currency made exchange difficult. Large landowners who could no longer export their crops began producing for local subsistence instead, manufacturing goods on their own estates rather than importing from the cities. The source identifies this as the beginning of the self-sufficient house economy that would eventually solidify into the manorialism of the Middle Ages.
City dwellers, meanwhile, moved into the countryside in search of food and protection. Many, made desperate by economic necessity, surrendered basic civil rights to large landowners in exchange for security. They became a half-free class known as coloni, tied to the land, their status made hereditary under later Imperial law. The source names this directly as an early model for medieval serfdom.
The battle that historians mark as the turning point took place at Naissus in 268 or 269. Emperor Claudius II Gothicus defeated a Gothic force that had invaded Macedonia and Greece, a population displaced from its lands on the Black Sea. Claudius had been born on the 10th of May 214 and had fought under Gallienus against several earlier usurpers before helping to overthrow that same emperor. His victory at Naissus drove back the Alamanni and recovered Hispania from the Gallic breakaway state.
He died of the Plague of Cyprian in 270, aged 56, and was succeeded by Aurelian, who had commanded the cavalry at Naissus. Aurelian, born on the 9th of September 214, would later be titled restitutor orbis, restorer of the world, by the Senate.
Aurelian reigned from 270 to 275 through what the source calls the worst of the crisis. He defeated the Vandals, the Goths, the Palmyrene Empire under Zenobia, and finally the remaining Gallic Empire under Tetricus I. Zenobia, described in the source as a remarkable and cultured stateswoman who had conquered Egypt in late 271 and held real power over the East since 267, was spared and allowed to retire; she later married a Roman senator. Tetricus I appears to have secretly arranged his own abdication with Aurelian before the Battle of Chalons; he was pardoned and appointed governor of Lucania in Southern Italy. By late 274, the Roman Empire had been reunited into a single entity.
Aurelian was then murdered in 275 by his own secretary, Eros, in response to what the source calls Aurelian's strict character, while he was preparing a campaign against Persia. A further cycle of short-reigning emperors followed until Diocletian, himself a barracks emperor, reunified the empire definitively after the Battle of the Margus in 285.
Diocletian had been born as Diocles on the 22nd of December 242, or possibly 243, in Dalmatia, the son, according to later tradition, of a scribe or a former slave. He was proclaimed emperor in Nicomedia after the death of Numerian in 284. His first act was to execute a man named Aper, whom he held responsible for that death, and he then marched west to defeat Carinus at the Battle of the Margus.
The empire he now governed had been fundamentally altered. Dozens of formerly thriving cities, especially in the Western Empire, had been ruined, their populations dead or dispersed, and the economic breakdown caused by constant warfare made rebuilding impossible. Major cities including Rome itself, which had not needed fortifications for many centuries, now surrounded themselves with thick walls. The Aurelian Walls in Rome were one of Aurelian's own construction projects.
Diocletian's response was structural. He began by sharing his rule with a colleague, then formally established what became known as the Tetrarchy, four co-emperors, in 293. He chose to rule from Nicomedia in Asia Minor rather than Rome itself, placing his colleague Maximian in Milan. The old Principate, the system Augustus had built around the fiction of a restored republic, was finished. Emperors no longer used the title princeps, meaning leading citizen. From Diocletian onward, they used domini, meaning lords.
The right of imperial succession still had no formal definition, and civil wars continued after Diocletian's abdication in the Civil wars of the Tetrarchy running from 306 to 324, until Constantine the Great emerged as sole emperor. But the empire had survived. It would continue in the West until 476, and in the East until 1453.
Common questions
What was the Crisis of the Third Century in Rome?
The Crisis of the Third Century was a period of Roman history, usually dated from 235 to 284, during which the empire nearly collapsed under repeated foreign invasions, civil wars, and economic disintegration. At its worst, the Roman state split into three competing polities: the Gallic Empire in the west, the Palmyrene Empire in the east, and the Italian-centered Roman Empire proper.
How did the Crisis of the Third Century begin?
The crisis began in 235 with the assassination of Emperor Severus Alexander by his own troops at Mogontiacum in Germania Superior. The soldiers then proclaimed Maximinus Thrax, a military commander of humble origins, as emperor, bypassing the Roman Senate entirely.
How many emperors were there during the Crisis of the Third Century?
Over fifty people claimed the title of augustus during the crisis period. Of these, about half received recognition from the Roman Senate and became legitimate emperors. With very few exceptions, every legitimate emperor during this period died violently, most killed by their own troops.
What ended the Crisis of the Third Century?
Emperor Aurelian (270-275) reunited the empire by defeating the Palmyrene Empire and the Gallic Empire, with the empire fully reunited by late 274. The crisis is said to have formally ended with Diocletian, who reorganized the Roman imperial government, economy, and military and established the Tetrarchy of four co-emperors in 293.
What caused the economic collapse during the Crisis of the Third Century?
Decades of currency debasement, as each new emperor inflated the coinage to pay military accession bonuses, caused hyperinflation that nearly destroyed the denarius by the end of the third century. Civil unrest made Rome's extensive trade network unsafe for merchants, forcing large landowners to shift from cash-crop export to local subsistence production, a transformation that the source identifies as a forerunner of medieval manorialism.
What role did the Plague of Cyprian play in the Crisis of the Third Century?
The Plague of Cyprian, possibly smallpox, devastated the Roman Empire from 249 to 262. The city of Alexandria alone experienced a 62% decline in population during this period. The plague weakened the army's ability to resist barbarian invasions, contributed to famine by causing farms to be abandoned, and deepened the political instability already caused by civil war.
What was the Gallic Empire during the Crisis of the Third Century?
The Gallic Empire was a breakaway state that split from Rome in 260 and lasted until 274. It controlled the western provinces of Hispania, Gaul, and Britannia, had its own capital at Trier, its own succession of emperors, and its own yearly-elected consuls. It was defeated and reunited with the Roman Empire by Aurelian.
All sources
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