Crisis of the Third Century (235-284): Empire on the Brink

The Crisis of the Third Century was a period of roughly fifty years, from AD 235 to 284, during which the Roman Empire came close to collapse. Emperors rose and fell in rapid succession, foreign enemies broke through the frontiers, an emperor was captured by the Persians, a terrible epidemic spread, and the silver coinage became almost worthless. For more than a decade the empire was split into three separate states. Yet it survived, and the reforms that followed created the late Roman Empire that lasted for centuries more.

Background: the Severan empire

At the start of the 3rd century the empire still looked strong. Septimius Severus (193–211) won a civil war, enlarged the army and raised soldiers’ pay. His son Caracalla granted citizenship to almost all free inhabitants and raised pay again. Paying for a bigger army strained the treasury, and emperors increasingly relied on the goodwill of their troops.

At the same time Rome’s neighbours were changing. In 224 the Parthian dynasty in Iran was overthrown by Ardashir I, founder of the Sasanian Empire, a more centralised and aggressive power that claimed the lands once ruled by the Achaemenid Persians. On the Rhine and Danube, smaller peoples were combining into larger confederations, such as the Alamanni, the Franks and the Goths, able to launch major raids.

The breakdown begins (235–253)

In March 235 soldiers at Mogontiacum (Mainz) murdered the young emperor Severus Alexander and his mother Julia Mamaea, angered by his attempt to buy peace from the Alamanni. They proclaimed Maximinus Thrax, a soldier of humble origin who had risen through the ranks. He was the first of the so-called “soldier emperors”, and he never visited Rome as emperor.

Maximinus’s heavy taxation provoked a revolt in Africa in 238, the “Year of the Six Emperors”. Gordian I and his son Gordian II were proclaimed in Africa and died within weeks; the Senate appointed Pupienus and Balbinus; Maximinus was killed by his own troops while besieging Aquileia; then the Praetorian Guard murdered Pupienus and Balbinus, leaving the teenage Gordian III as sole ruler.

Gordian III died in 244 during a campaign against Shapur I of Persia, and his successor Philip the Arab made a costly peace. Philip celebrated Rome’s thousandth anniversary with great games in 248, but was overthrown in 249 by Decius, a senator commanding on the Danube. Decius ordered a universal sacrifice to the gods that led to the Decian persecution of Christians. In June 251 he and his son were killed by the Goths under Cniva at Abritus, in modern Bulgaria, the first Roman emperor to die in battle against a foreign enemy.

Catastrophe (253–268)

Around 249 a pandemic known as the Plague of Cyprian, after the bishop of Carthage who described it, began to spread through the empire. It continued in waves for perhaps fifteen years. Its cause is unknown; smallpox, a viral haemorrhagic fever and other diseases have been suggested. Death tolls cannot be calculated, but contemporaries described heavy mortality in cities such as Alexandria.

In the east, Shapur I captured the frontier city of Dura-Europos around 256 and sacked Antioch, one of the largest cities in the empire, probably in 253. In 260 the emperor Valerian was defeated and captured near Edessa, an event described in the article on the Battle of Edessa. He died in captivity, the first Roman emperor to be taken prisoner by a foreign enemy.

Valerian’s son Gallienus, now sole emperor, faced simultaneous disasters. Alamanni and Juthungi raided into Italy; Franks crossed Gaul and reached Spain; Goths and other peoples raided by sea across the Black Sea and the Aegean, sacking cities in Asia Minor and, in about 267–268, Athens. Several usurpers rose against him in the Balkans, the east and Egypt, most of them proclaimed by armies that felt abandoned by a distant emperor.

Gallienus responded with important changes. He built up a mobile reserve of cavalry, based for a time at Mediolanum (Milan), that could move quickly to wherever a threat appeared. He also stopped appointing senators to command legions, opening the top military posts to professional officers who had risen from the ranks. These measures laid foundations for the later Roman army. He ended his father’s persecution of Christians in 260, granting them a period of toleration that lasted some forty years.

A divided empire

In 260 the general Postumus was proclaimed emperor on the Rhine and created what historians call the Gallic Empire, controlling Gaul, Germany, Britain and for a time Spain. It had its own emperors, consuls and coinage until 274.

In the east, Odaenathus, a leading citizen of the caravan city of Palmyra in Syria, defeated Persian forces and was given wide powers by Gallienus. After his murder in about 267, his widow Zenobia ruled for their young son and from 270 seized Egypt and much of Asia Minor. The story is told in Zenobia and the Palmyrene Empire. For a few years the Roman world was divided into three blocs: the Gallic west, the central empire around Italy and the Balkans, and the Palmyrene east.

Money and the economy

The main silver coin of the period, the antoninianus, was introduced by Caracalla in about 215. To pay soldiers, emperors steadily reduced its silver content. By the 260s and 270s it was a bronze coin with a thin silver wash, often containing only a few per cent of silver. People hoarded older, purer coins and spent the new ones, so that hoards from the period contain huge numbers of debased pieces; the Frome Hoard found in Somerset in 2010, with more than 52,000 coins, is a famous example. Prices rose sharply, especially in the later part of the century, and the state increasingly collected taxes and paid its servants in goods rather than coin.

How deep the economic crisis went is debated. Hoards of coins buried and never recovered, damaged towns and new defensive walls show insecurity in many frontier provinces. But some regions, such as North Africa and parts of the east, continued to prosper, and modern historians warn against assuming a single empire-wide collapse.

Recovery and the end of the crisis

Gallienus was murdered in 268 by his own officers. His successor Claudius II won a major victory over the Goths at Naissus (Niš) in 268 or 269 and took the title Gothicus, but died of plague in 270.

Aurelian (270–275) completed the recovery. He drove invaders out of Italy and began the Aurelian Walls around Rome in 271. He defeated Zenobia in 272 and destroyed Palmyra after a second revolt in 273, and in 274 defeated the last Gallic emperor, Tetricus, near Châlons. He gave up the province of Dacia north of the Danube, attempted a currency reform and promoted the cult of the Unconquered Sun, Sol Invictus. Coins and inscriptions hailed him as restorer of the world, but he was murdered in 275 by officers who feared punishment.

Short reigns continued: Tacitus, Florian, Probus, Carus and his sons Carinus and Numerian. In November 284 the army in the east proclaimed Diocletian, a Dalmatian officer, who defeated Carinus in 285. Diocletian ruled for more than twenty years and introduced the Tetrarchy, a system of four co-rulers, along with reforms of provinces, the army, taxation and coinage. Most historians date the end of the crisis to his accession.

The empire that emerged was different from that of the Severans. Emperors now came mostly from the Balkan officer class rather than the Roman Senate, and they spent their reigns near the frontiers rather than in Rome. Cities across the empire, including Rome itself, had built walls. The army was larger and more mobile, and the tax system was rebuilt around payments in kind assessed by regular census. Court ceremony grew more elaborate, presenting the emperor as a remote, almost sacred figure, a style historians call the Dominate.

Key people

• Maximinus Thrax (r. 235–238): the first soldier emperor, killed by his troops at Aquileia.
• Decius (r. 249–251): ordered universal sacrifice; killed by the Goths at Abritus.
• Valerian (r. 253–260): captured by the Persians at Edessa.
• Gallienus (r. 253–268): ruled through the worst years; reorganised the army, creating mobile cavalry forces and excluding senators from military command.
• Shapur I (r. c. 240–270): Sasanian king who defeated three Roman emperors and recorded his victories in a trilingual inscription at Naqsh-e Rostam.
• Aurelian (r. 270–275): reunited the empire.

Myths and facts

The phrase “Crisis of the Third Century” is a modern label, and some historians prefer to speak of a period of transformation. The crisis was real, but it was not uniform: some provinces suffered repeated invasions, while others saw little fighting.

It is also often said that the emperors of this era were all crude soldiers. Valerian and Gallienus came from a senatorial family, Tacitus was traditionally described as an elderly senator, and Gallienus was a patron of philosophy and the arts.

Timeline

• 235, March: Severus Alexander murdered; Maximinus Thrax proclaimed.
• 238: Year of the Six Emperors.
• c. 249: The Plague of Cyprian begins.
• 251, June: Decius killed by the Goths at Abritus.
• 260: Valerian captured by Shapur I; Postumus founds the Gallic Empire.
• 268: Gallienus murdered; Goths defeated at Naissus (268 or 269).
• 272–273: Aurelian defeats Zenobia and destroys Palmyra.
• 274: Aurelian defeats Tetricus and reunites the empire.
• 284, 20 November: Diocletian proclaimed emperor.

Why it matters

The Crisis of the Third Century tested the Roman Empire almost to destruction and changed it permanently. The empire that emerged under Diocletian and Constantine had a larger army, heavier taxation, walled cities, emperors who ruled from frontier capitals rather than Rome, and a court ceremony that set the ruler far above his subjects. Understanding the crisis is key to understanding how the Roman world entered late antiquity.