Maximian - Carausius

Carausius

Although most of Gaul was pacified, regions bordering the English Channel still suffered from Frankish and Saxon piracy. The emperors Probus and Carinus had begun to fortify the Saxon Shore, but much remained to be done. For example, there is no archaeological evidence of naval bases at Dover and Boulogne during 270–285. In response to the pirate problem, Maximian appointed Mausaeus Carausius, a Menapian from Germania Inferior (southern and western Netherlands) to command the Channel and to clear it of raiders. Carausius fared well, and by the end of 285 he was capturing pirate ships in great numbers.

Maximian soon heard that Carausius was waiting until the pirates had finished plundering before attacking and keeping their booty himself instead of returning it to the population at large or into the imperial treasury. Maximian ordered Carausius' arrest and execution, prompting him to flee to Britain. Carausius' support among the British was strong, and at least two British legions (II Augusta and XX Valeria Victrix) defected to him, as did some or all of a legion near Boulogne (probably XXX Ulpia Victrix). Carausius quickly eliminated the few remaining loyalists in his army and declared himself Augustus.

Maximian could do little about the revolt. He had no fleet – he had given it to Carausius – and was busy quelling the Heruli and the Franks. Meanwhile, Carausius strengthened his position by enlarging his fleet, enlisting Frankish mercenaries, and paying his troops well. By the autumn of 286, Britain, much of northwestern Gaul, and the entire Channel coast, was under his control. Carausius declared himself head of an independent British state, an Imperium Britanniarum and issued coin of a markedly higher purity than that of Maximian and Diocletian, earning the support of British and Gallic merchants. Even Maximian's troops were vulnerable to Carausius' influence and wealth.