Antoninianus - Tetricus I PAX AVG

Tetricus I issued this coin during the death throes of the Gallic Empire, a breakaway state that had survived for over a decade by the time PAX AVG types were being struck at Cologne. The irony is pointed: Pax coinage flooded from the mint precisely as Aurelian was assembling the force that would crush Tetricus at the Battle of Châlons in 274. Tetricus himself surrendered — possibly by prior arrangement — and was permitted to live, later serving as a corrector in southern Italy.

The billon content by this stage was severely debased, barely a silver wash over copper.