Æ24 - Gallienus ΝΙΚΟΠΟΛΙϹ, Δ

Nicopolis ad Isthmon was a small Achaean civic mint that issued bronze coinage sporadically under imperial authority, and the Δ control mark on this piece was one of several used to organize production runs — likely indicating a specific officina or series batch rather than a magistrate. Gallienus ruled the eastern provinces through much of his reign while his co-emperor Postumus held the breakaway Gallic Empire in the west, yet civic bronzes like this continued flowing from Greek mints with remarkable consistency, supplying local markets that had little access to the debased silver antoniniani flooding the rest of the empire.