Antoninianus - Tetricus I PIETAS AVGVSTOR

Tetricus I issued this coin from Cologne during the final, chaotic months of the Gallic Empire — a separatist state that had functioned as a buffer against Germanic incursions for over a decade. By 273–274, the situation had deteriorated badly enough that Tetricus reportedly appealed secretly to Aurelian to come and end it, preferring Roman subjugation to being killed by his own mutinous troops. Aurelian obliged at the Battle of Châlons. Tetricus survived and was paraded in Aurelian's triumph before being quietly retired to a provincial governorship in Italy.

The billon content by this point was negligible — the antoninianus had been debased so aggressively that many issues are essentially bronze with a flash silver wash.