Rising through the ranks to become an admiral, Marcus Aurelius Mausaeus Carausius declared himself emperor of Britain and later northeast Gaul after being sentenced to death for embezzlement. Although his reign ended in assassination in 293AD, it was successful enough to last for seven years. Carausius’s breakaway revolt was one of a series that led to an overhaul in the Roman Empire’s administration.
The Roman Political Situation in the Third Century AD
From the mid-third century onwards, the Roman Empire was troubled by a series of wars across its various eastern and western frontiers. This situation continued until Emperor Diocletian and his colleague Maximian restored stability in the late century.
Most of these revolts involved barbarian tribes and client nations that were beginning to challenge Rome’s authority. However, there were also instances of Roman officials setting up mini empires in trouble spots. In 260AD, General Postumus declared himself emperor of Gaul, ostensibly to repel barbarian Germans and Franks from the border. Then, in 286 AD, came the miniature empire of Carausius.
The Career of Carausius
Carausius was a member of the Belgium tribe of the Menapii. He reputably began his career as a helmsman, but in the 280s, Maximian, Diocletian’s colleague, promoted him to commander of the Classis Britannica or British fleet. Carausius’s mission was to protect the sea and coastline from Frankish and Saxon pirates.
Using Boulogne as his base, Carausius had great success — until he was accused of embezzling the pirate’s spoils. Under sentence of death, Carausius fled to Britain and — aided by the Frankish mercenaries he had previously been sent to repel — declared himself emperor.
Diocletian and Maximian’s Co-Emperor
The German wars occupied Maximian until spring 288AD. However, a respite in the fighting allowed him to turn his attention to Carausius. Maximian began to build a fleet to cross the Channel to deal with the rebellion. In the meantime, he sent Constantius Chlorus (father and grandfather of the future emperors Constantine and Julian) to defeat Carausius’s Frankish allies. He succeeded, severely weakening the rebel emperor’s position. However, the campaign failed when Maximian’s fleet was destroyed, crossing the Channel in 289 AD.
Unable to defeat Carausius and still preoccupied with Germany, Maximian and Diocletian had no choice but to recognise the rebel commander as a co-emperor to secure at least part of the western frontier. As a consequence, Carausisu became responsible for northeastern Gaul as well as Britain.
It seemed that Carausius had achieved legitimacy at last. He even minted his own currency in Rouen, part of his newly acquired Gaulish province. Using images of peace and concord, they expressed Carausius’s belief in the stability of his reign.
Carausius’s Downfall
However, for Maximian, the situation with Carausius was nothing more than a convenient truce. To prevent wrangling over the succession and, at the same time, create a stable power base, in 293AD, Diocletian reformed the administrative system of the empire. He instigated a division of power between two emperors, the Augusti and their deputies, known as the Caesars, who were effectively emperors in waiting. He and Maximian were Augusti with Galerius as Caesar in the east and Constantius Chlorus the Caesar in the west.
In 293AD, Maximian sent Constantius Chlorus to overthrow Carauscius. This time, he was successful. Boulogne, Carausius’s base, was besieged and eventually surrendered.
However, Chlorus never captured the rebel emperor. Instead, Carauscius was murdered by his finance minister Allectus who subsequently escaped to Britain to take his former master’s place.
The Aftermath of Carausius’s Revolt
Allectus did not enjoy his power for long. In 296AD, Maximian overthrew Allectus and reabsorbed Britain into the empire. Diocletian’s administrative reorganisation was successful, and the tetrarchy slowly began to stabilise the empire’s frontiers, ensuring that an empire within an empire would not occur again.
Resources
Hazel, J (2001) Who’s Who in the Roman World. Routledge.
