Æ29 - Valerian and Gallienus ΕΠΙ ΑΡΧ ΑΥΡ ΔΙΟΓΕΝΟΥϹ ΔΙΔΥΜΕΙΑ ΜΕΙΛΗϹΙΩΝ

Miletus struck this joint issue during the co-reign of Valerian I and Gallienus, a pairing that was itself a product of military emergency — Valerian elevated his son to co-emperor almost immediately upon seizing power in 253, partly to secure the western frontier while he moved east against Shapur I. The magistrate named in the legend, Aurelius Diogenes, was the archon responsible for authorizing the issue, a civic dignity that carried genuine financial accountability in Asia Minor's provincial minting system.

The Didymeia festival referenced in the coin's legend was tied to the sanctuary of Apollo at Didyma, just south of Miletus — one of the ancient world's largest oracular temples, still under intermittent construction at this date after centuries of work.