Third century Romano British coins.

Carausius & Maximian
1. & 2. Carausius, A.D. 288-93 [?Clausentum=Bitterne], co-emperors, secular  games.
3. Maximian [London]


Carausius, Allectus & Magnus Maximus
4. Carausius,  A.D. 288-93,Wolf & twins.
5. Allectus, A.D. 293-6, Sun.
6. Magnus Maximus[London]
7. Carausius [Clausentum]

Carausius  produced a short lived independent regime soon after the empire of Postumus ended. Postumous had visited Britain and Carausius, as indicated by his coinage, modelled himself on the emperor (7. SALVS, well-being).Carausius mimics Postumus
Carausius had his coinage minted at London (M.L.=Moneta Londinensis) and perhaps at Bitterne (C.=Clausentum?) not far from Portchester.
The coinage indicates a peace he extorted from Rome as they are inscribed PAX AVGGG -"The peace of the emperors"- the repetition of the final letter indicating three emperors are mentioned,  himself  with Diocletian & Maximian.
The Secular Games were normally held in Rome periodically to purify the taints of the past and install a new golden Age. The coin (1) indicates these games may have been held in London.Later Carausius turned pirate and defeated Maximian at sea., these coins show he at least was granted outward recognition, he even describes the other two as his brothers when the heads are labelled CARAVSIVS ET FRATRES SVI -"brothers"- and he also issued coins in the names of both of them.
Later Britain became the base for usurpers when the governors Magnus Maximus (A.D. 383-88) and Constantine III (A.D. 407-411) invaded the continent and sought successfully, in  the case of Magnus Maximian, to reach Rome.
For a time Carausius controlled Northern France, his coin circulation indicate the limits to his influence in this region.

Source: Roman History from Coins, Michael Grant, C.U.P., 1957.