Carausius

Marcus Aurelius Mausaeus Valerius Carausius (died 293) was a Roman military commander in Britain. In 286 he was sentenced to death for corruption, but proclaimed himself emperor, and broke away from the empire, ruling over Britannia and part of Gaul. In 293 his Treasurer Allectus assassinated Carausius and took over command of the province. In 296 the rebel empire came to an end when Allectus was defeated and killed by the the forces of the Roman emperor Constantius.