 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 <unk> 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 . 
