Carausius Rebellion (286–293 CE)

Bringing Order to Chaos: The Armies of Diocletian

Maximian, as Emperor of the West, had his own military problems. Of these, the most intractable was presented by Carausius, a rebellious admiral of the British Channel fleet. Irrepressible, Carausius was for some time endured by the two “Augusti” as a kind of supernumerary colleague in Britain and north Gaul. Eventually, Maximian’s “Caesar”, Constantius, drove him from Boulogne and, continuing the war against Carausius’ murderer and successor Allectus, restored Britain to its former allegiance.

The rebellion by Carausius occurred in Britain beginning in 286 and, with his death in 293, continued under his successor until its final defeat in 296 or 297. Carausius successfully commanded forces in the Bagaudae wars in 286 CE, earning distinction. After his success Emperor Maximian charged him with outfitting a fleet and destroying the German pirates who were menacing the shores along the English Channel, after which the two had a falling out, perhaps because of Maximian’s promotion to caesar in December 285, perhaps because Carausius may have been stealing the loot taken from pirates, or because Carausius’s enemies conspired against him. Maximian declared Carausius an outlaw and ordered his execution; at this point Carausius seized power.

Carausius seems to have made northern Gaul his base of operations in 286 around the city of Rouen, where he established a mint issuing gold and bronze coins. These gold coins were probably used to bribe the military units along the Rhine to ally with him and to keep other units in his expeditionary army loyal. His power must have seemed secure and strong enough to scare Maximian, who moved his gold stocks from Gaul to Rome for safety. Maximian may have first had to deal with the Germans, who made a series of raids. Some of these tribes came from a great distance, and Carausius was probably not in league with them; however, the occasion helped him. Maximian now ordered an expeditionary force north to retake the lost territories.

During this early period when Carausius held northern Gaul, he successfully convinced units and/or commanders from a Rhine legion to join him. This would have been a severe shock to Maximian, since the rebellion could threaten the entire Rhine region. Maximian’s campaign in Germany in the summer of 286 may not have been only to counter the Germans but also to reestablish control of and loyalty among the Rhine legions. Carausius probably controlled the region around Rouen and Bolougne, which housed his new fleet. Maximian marched north in late 288 or early 289 and retook northern Gaul, forcing Carausius back across the channel, where he controlled only Britain. Associated with this campaign may have been the war against Carausius’s allies, the Franks, in 288 or 289. This war deprived Carausius of a valuable ally, which previously had distracted Maximian.

After the Frankish war, Carausius was left to deal with Maximian alone. Since Carausius possessed the fleet, he probably controlled the English Channel from his British bases. Maximian now began to build a new fleet inland away from the channel. This fleet was then floated downstream and into the sea. The fleet was probably built inland to hide Maximain’s plan and due to the readily accessible timber along the Mosel and Rhine Rivers. The fleet was probably built in 289, since a contemporary source for that year indicates hope for a quick victory (Nixon and Rodgers 1994, 73). A second and later contemporary source does not mention the fleet or the campaign (Nixon and Rodgers 1994, 79).

There are several possibilities to explain the discrepancy among contemporary sources. Carausius may have defeated the new fleet, a storm may have destroyed it, or some third party, Saxon pirates or the like, may have attacked on the open seas. The fleet may have been destroyed by land forces such as the Germans before it reached the channel, or the fleet was never used, although the latter is highly unlikely, since Maximian had just spent a year building it. These possibilities or even some others seem to have played havoc. The two most likely reasons were that Carausius defeated Maximian or a storm shattered the fleet. Contemporary sources would not indicate Carausius’s victory, and a later source seems to mention a storm (Nixon and Rodgers 1994, 130).

After Maximian’s setback, Carausius launched an offensive to regain northern Gaul, successfully taking the key city of Boulogne and other regions. This enabled him to control the channel and the surrounding regions. From here Carausius could strike throughout the channel region and move into the center of Gaul and east into the German regions. He made Boulogne his chief base of operations beginning sometime after 289, during which time he may have strengthened the defensive works around the city. In addition, he may have forged an alliance with the Alamanni. Carausius also began his political attempt to seek recognition. This is mainly seen in his coinage, where he called himself caesar and began issuing consular coinage. There is no evidence that Rome recognized his new political call. In addition, Carausius issued coins with the central emperors Diocletian and Maximian and his portrait with them with the legend “Carausius Et Fratres Sui” (Carausius and his Brothers); Diocletian did not reciprocate this new overture.

Their issue ceased when Diocletian elevated Constantius, a general, to become Maxiamian’s caesar, or lieutenant. There may have been some sort of peace agreement with Carausius after the loss of the fleet, since a later fourth-century Roman author, Aurelius Victor (320-390), records the contemporary victories over the Persians, in the Alexandrian rebellion, and over African tribes (all post-290) and then stated that only Carausius was allowed to retain his rule over the British Island, since he was competent to command and defend its inhabitants against warlike tribes (Victor and Bird 1994, chap. 39). This statement by a historian 50 years later does not necessarily mean that any official agreement was made, but the implication of him being allowed to rule over Britain seems to indicate so. Another later author, the fourth-century historian Eutropius, went even further, stating that a peace treaty had occurred, since Carausius was so skilled in war (Watson et al. 1853). This peace may have been a real event or merely a representation of the practical events. Carausius would continue to hold northern Gaul until the summer of 293.

In 293 Constantius attacked northern Gaul, and during the battle for Boulogne, Carausius was assassinated by his second-in-command, Allectus. Carausius had been successful and adept at defeating the central government, and with his assassination the rebellion lost its true leader, making defeat more likely. Constantius, after a setback in which he lost another fleet, attacked Britain in 296. With one part of the fleet landing in the south while he took a second part toward the east, Allectus was forced to defend two possible attacks. The force that landed in the south marched toward London, and Allectus rode out to meet it. At an undetermined site the two forces met, and Allectus was defeated and killed. Constantius now landed in the east and marched on London.


A major usurper during the late 3rd century A.D., who controlled Britain and much of modern Gaul. Carausius had humble origins in Messapia but won fame in the campaigns of Emperor Maximian against the Franks and the Bagaudae in 286. Looking for a competent officer to eradicate the Frank and Saxon pirates in the Channel, Maximian chose Carausius.

He proved a brilliant admiral but was accused of keeping recovered plunder for his own use and of pressing captured pirates into his own fleet. Sentenced to death, he sailed to Britain in late 286 or early 287, declaring himself independent of imperial control. The Britons greeted him cheerfully and helped him to consolidate his power. Carausius soon began to seize large parts of the Gallic coast. In April of 289, Maximian finally moved against him, only to suffer defeat at Carausius’ hands. The emperor was reduced to making a treaty with him instead. Carausius declared his triumph, issuing at first an irregular and then an imperial coinage, with the presumptuous words: “Carausius and his brothers, Diocletian and Maximian.” Ironically, Carausius provided the TETRARCHY exactly what it needed in Britain. He resisted the incursions of the Picts, repaired Hadrian’s Wall and kept the regions secure. His independence, however, could not be tolerated, and Diocletian waited until the time was ripe to strike.

In 293, Emperor Constantius I Chlorus, Diocletian’s junior, launched a massive assault on Carausius’ holdings in Gaul. The port of Gesoriacum (Boulogne) was blockaded by Constantius, while Carausius’ main fleet remained in Britain to repel an invasion. The city fell, but just barely; reinforcements were prevented from arriving by a great mole stretched across the harbor. These initial setbacks were compounded as Constantius cleared the entire region of Gaul. Having lost his continental territories, Carausius suffered other political difficulties as well, until his chief minister, ALLECTUS, became disenchanted and killed him in 293, taking over his ships, troops and his claim to supremacy in Britain.

ALLECTUS (fl. late 3rd century A.D.)

A rationalis or minister of finance to the usurper CARAUSIUS. In 293, his ambitions led him to assassinate his master and seize power for himself in Britain and in some provinces of Gaul. Allectus was apparently a gifted soldier and sailor, and his rule lasted for three turbulent years. Sometime around 295-296, Constantius I (Chlorus) resolved to end the usurpation of power and set sail with two fleets to Britain, commanding one fleet and entrusting the other to Praetorian Prefect Asclepiodotus. After losing his enemy in a fog, Allectus disembarked his fleet and prepared for battle. Near Hampshire, Asclepiodotus fought and routed Allectus, and shortly thereafter Allectus was killed. Constantius entered London and thus found a power base for himself and his son, Constantine the great.

Further Reading Casey, P. J. 1995. Carausius and Allectus: The British Usurpers. New Haven, CT: Yale University Press. Clayson, Alan. 2010. Nixon, C. E. V., and Barbara Saylor Rodgers, eds. and trans. 1994. In Praise of Later Roman Emperors: The Panegyrici Latini. Berkeley: University of California Press. Victor, Sextus Aurelius, and H. W. Bird. 1994. Liber De Caesaribus. Liverpool: Liverpool University Press. Watson, J. S., et al. 1853. Justin, Cornelius Nepos, and Eutropius. London: Henry G. Bohn. White, Donald A. 1961. Litus Saxonicum: The British Saxon Shore in Scholarship and History. Madison: University of Wisconsin Press.