Æ22 - Valerian and Gallienus ΑΜΙϹΟΥ ΕΛΕΥΘΕ

Amisus held the status of a free city — eleuthera, as the obverse legend announces — a privilege originally granted under Pompey's reorganization of Pontus in 65 BC and jealously maintained through successive imperial regimes. That autonomy meant the city retained the right to strike its own bronze coinage without direct imperial authorization, which is precisely why a joint issue naming both Valerian and Gallienus could emerge from a provincial mint at all. The co-emperorship began in 253 AD when Valerian elevated his son, a pairing that lasted until Valerian's capture by Shapur I — the only Roman emperor ever taken prisoner by a foreign enemy.