Æ22 - Gallienus sole reign) (ΙΕΡΑϹ ΝΙΚΕΠΟΛΕΩϹ, Δ

Nicopolis ad Isthmon — not to be confused with the more prolific Nicopolis ad Mestum in Moesia — was a minor Achaean mint whose output under Gallienus falls entirely within the sole reign period after 260, when the capture of his father Valerian by Shapur I left him ruling alone. The Δ control mark on this issue is a workshop or sequence designator whose exact administrative function remains debated among provincial specialists, but its presence confirms a structured, if small-scale, civic minting operation continuing through one of Rome's most fractured decades.