Cassianii

Marcus Cassianius Latinius Postumus ( 259–269) was a Roman commander of Batavian origin, who ruled as emperor of the splinter state of the Roman Empire known to modern historians as the Gallic Empire. The Roman army in Gaul threw off its allegiance to emperor Gallienus around the year 260, and Postumus assumed the title and powers of Emperor in the provinces of Gaul, Germania, Britannia, and Hispania. He ruled for the better part of ten years before he was murdered by his own troops.

possible 3rd century Roman imperial usurper