The Crisis of the Third Century was a period of about fifty years, usually dated AD 235 to 284, when the Roman Empire nearly broke apart. Short-lived emperors, civil war, invasions, plague and inflation hit at once, and for a time two breakaway states split off.
Key takeaways
- The crisis is usually dated from the death of Severus Alexander in AD 235 to the rise of Diocletian in AD 284.
- Emperors were often made and killed by their own soldiers, and dozens of people claimed the throne.
- Our map shows the empire at 4.81 million km² in AD 211 and 4.72 million km² in AD 395, so the lands were mostly intact afterwards.
- The map does not draw the Gallic or Palmyrene breakaway states, so the crisis leaves no mark of its own on the outlines.
How the Crisis of the Third Century works
The Crisis of the Third Century is the name for the troubled decades between the death of the emperor Severus Alexander in AD 235 and the rise of Diocletian in AD 284. Some sources date the end to AD 285, after Diocletian beat his rival Carinus [1]. Several problems came together.
- Emperors made by soldiers. After Severus Alexander was killed by his own troops, the soldiers proclaimed Maximinus Thrax, the first of the "barracks emperors". Claimants kept appearing. One count gives at least 26 accepted by the Senate, another says more than fifty people claimed the title, and sources differ on how many were legitimate [1].
- Pressure from outside. The Sasanian Persians captured the emperor Valerian in AD 260, and he died in captivity [1]. Other peoples raided across the frontiers as well.
- Plague. An outbreak known as the Plague of Cyprian struck from about the middle of the century. Sources give different dates, and it may have been smallpox [1].
- Money. Coins were debased, with less silver in each, which caused serious inflation. By the end of the century the silver denarius had effectively lost its value [1].
- Breakaway states. Two regions split from central control: the Gallic Empire in the west and the Palmyrene Empire in the east. Both were brought back by the emperor Aurelian, with the Palmyrene capital destroyed in AD 273 and the remains of the Gallic state defeated in AD 274 [1].
Historians disagree about how much of this was truly a collapse and how much was a run of bad years that differed from region to region. Many parts of the empire carried on much as before while others suffered. Diocletian, who ended the crisis, reformed the empire's government, as the tetrarchy shows.
An example from our data
Our slider does not have a date in the middle of the crisis, but it does have one on either side. At AD 211, just before, the outline covers about 4.81 million km² with 43 provinces. At AD 395, well after, it is about 4.72 million km² with 42 provinces. That is a small change, which tells you the empire survived the crisis in territory even though it was changed in government. The first outline uses the the Ancient World Mapping Center outline, and the second is rebuilt from the provinces Rome held, so the small gap is partly down to method.
The map's province outlines are those of AD 200, before Diocletian's reforms. It does not show the Gallic Empire or the Palmyrene Empire, and it has no layer for legions, invasions or battles. For why the empire eventually did divide, see why it fell twice.
The thing people get wrong
The crisis is sometimes described as the moment the empire "fell" or began its decline. It did not fall. The empire was reunited by the end of AD 274 [1] and Diocletian rebuilt its government. The crisis changed how Rome was ruled, and it is often used to mark the end of the Principate, but the empire went on for generations in the West and far longer in the East.
Frequently asked questions
How long did the Crisis of the Third Century last?
About fifty years. It is usually dated from AD 235, when Severus Alexander died, to AD 284, when Diocletian came to power. Some sources give 285.
How many emperors were there?
Sources give different counts. One count has at least 26 claimants accepted as legitimate, and another says more than fifty people claimed the title.
Did the Roman Empire lose territory in the crisis?
Not for good. Two regions broke away for a time, but Aurelian brought them back by AD 274. Our map shows 4.81 million km² before and 4.72 million km² after.
Sources
- Crisis of the Third Century, Wikipedia.
- Roman Empire, Wikipedia.
- Every figure from our own map is worked out from the datasets on the data sources page (checked against Ancient World Mapping Center outlines and Pleiades).