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 late 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. Maximian appointed Augustus Spurred by the crisis with Carausius, on 1 April 286, Maximian took the title of Augustus (emperor). This gave him the same status as Carausius – so the clash was between two Augusti, rather than between an Augustus and a Caesar – and, in Imperial propaganda, Maximian was proclaimed Diocletian's brother, his equal in authority and prestige. Diocletian could not have been present at Maximian's appointment, causing Seeck to suggest that Maximian usurped the title and was only later recognized by Diocletian in hopes of avoiding civil war. This suggestion has not won much support, and the historian William Leadbetter has recently refuted it. Despite the physical distance between the emperors, Diocletian trusted Maximian enough to invest him with imperial powers, and Maximian still respected Diocletian enough to act in accordance with his will. In theory, the Roman Empire was not divided by the dual imperium. Though divisions did take place – each emperor had his own court, army, and official residences – these were matters of practicality, not substance. Imperial propaganda from