Base-silver radiate of Carausius, with the emperors Diocletian and Maximian

Roman Britain, late 3rd century AD

The ancient British Empire

If you had told an ancient Roman that Britain would go on to acquire the most widespread empire in world history, his response would have been utter disbelief. At the time Britain was one of the poorer and certainly the most remote part of the Mediterranean-centred Roman Empire. Yet, the years AD 287-96 were remarkable in the history of Roman Britain. The island, together with the northern coast of France, had its own emperor. Carausius (died AD 293), originally commander of the channel fleet, had been accused of corruption and assumed imperial power in order to save himself from punishment. His 'empire' was probably based at the main commercial centre of Londinium (London), or at Camulodunum (Colchester).

Carausius had limits to his imperial ambitions, after all he had only rebelled to save his own life. It is clear from some of the coins he produced that he would have been perfectly content to rule Britain and north Gaul and hope for recognition by the legitimate emperors: Diocletian who ruled the east, and Maximian who ruled in the west. However, the official Roman forces fought back and took northern France and, as he began to loose territory, Carausius was killed and replaced by his own chief officer, Allectus. However, Allectus was soon defeated and killed himself, ending Britain's existence as a separate empire.

This coin of Carausius is a very fine example of his hopes for acceptance as a co-emperor. The three busts show Carausius on the left, in the company of Diocletian as the senior emperor in the centre, and Maximian on the right. The Latin inscription reads CARAVSIVS ET FRATRES SVI ('Carausius and his brothers').

B. Jones and D. Mattingly, An atlas of Roman Britain (London, Guild Publishing, 1990)

P.J. Casey, Carausius and Allectus, the Br (Yale, 1995)