'Antoninianus' of Carausius
Carausius was admiral of the Channel Fleet, which was based on the channel ports to give protection from Saxon and Frankish raiders. Success in this role enabled him to proclaim himself emperor in Britain and northern Gaul. One of his first actions was to set up mints in London and elsewhere. The ML at the bottom of the reverse of this coin stands for Moneta Londinensis, 'London Mint'. The meaning of XXI is disputed. The figure on the reverse is that of Peace: PAX AUG(usta), 'Imperial Peace'. Coinage was used to convey propaganda to the masses and with this message Carausius sought to promote peace and stability. He was murdered by his finance minister, Allectus, in AD293.