Stater - Rheskuporis IV Valerian and Gallienus

By 264 AD the Bosporan Kingdom had been issuing billon staters with steadily declining silver content for generations, the coinage serving as much as a diplomatic instrument as a circulating medium — Bosporan rulers maintained their position partly through careful acknowledgment of Roman imperial authority, which is why Roman emperor portraits appear alongside the local dynast on these coins. Rheskuporis IV ruled during one of Rome's most chaotic periods, the so-called Crisis of the Third Century, when Valerian and Gallienus co-held the emperorship in an increasingly fractured empire.

Valerian would be captured by the Sasanian king Shapur I the following year — the only Roman emperor ever taken prisoner in battle.