Marcus Aurelius Mausaeus Carausius, (died AD 293, Britain), was a Roman military officer. He created a short-lived independent state in Britain.
He was born in Menapia, a district between the Scheldt and Meuse rivers (now in Belgium) and was a pilot by profession. He had won renown in the Roman war against the Bagaudae. About AD 285, Maximian, (who was coruler with the emperor Diocletian), had assembled a large naval force in order to counter the Franks and Saxons who were plundering the coasts of Spain and Gaul.
… Carausius, who, though of very mean birth, had gained extraordinary reputation by a course of active service in war, having received a commission in his post at Bononia [Boulogne], to clear the sea, which the Franks and Saxons infested, along the coast of Belgica and Armorica [i.e. along the northern coast of Gaul] …
Eutropius Breviarium Ab Urbe Condita IX, 21
Carausius was given command of the fleet, which was based at Gesoriacum (modern Boulogne). There were rumours that Carausius would wait until the pirates had carried out raids, then would attack them and seize their cargoes for himself. Maximian consequently ordered Carausius’s death, but Carausius escaped with his troops into Britain, where he set himself up as ruler, with the title of Augustus.
… [Carausius] having captured numbers of the barbarians on several occasions, but having never given back the entire booty to the people of the province or sent it to the emperors, and there being a suspicion, in consequence, that the barbarians were intentionally allowed by him to congregate there, that he might seize them and their booty as they passed, and by that means enrich himself, assumed, on being sentenced by Maximian to be put to death, the imperial purple, and took on him the government of Britain.
Eutropius <i>Breviarium Ab Urbe Condita</i> IX, 21
He trained the locals as sailors and soon controlled the western sea and ruled Gaul as far as Rotomagus (modern Rouen). Carausius probably had his capital in London, and it is fairly certain that he established a mint there. He built and reinforced the Saxon Shore Fort of Portus Adurni (Portchester).
Carausius was, of course, maligned by imperial chroniclers. Diocletian and Maximian failed in several attempts to dislodge him and acknowledged him as ruler of Britain in 290. Constantius I drove Carausius from Gesoriacum, his European base, in 293, and that same year Carausius was slain by his finance minister, Allectus, who succeeded him for three years.
… With Carausius, however, as hostilities were found vain against a man eminently skilled in war, a peace was at last arranged. At the end of seven years, Allectus, one of his supporters, put him to death, and held Britain himself for three years subsequently, but was cut off by the efforts of Asclepiodotus, praefect of the praetorian guard. …
Eutropius Breviarium Ab Urbe Condita IX, 22