Æ25 - Valerian and Gallienus ΝΙΚΑΙΕΩΝ

Nicaea was one of the most prolific civic minting authorities in Bithynia, issuing bronze coinage under joint imperial names throughout the third century. The co-reign of Valerian and Gallienus — father and son ruling simultaneously from 253 until Valerian's capture by the Sasanian king Shapur I at Edessa in 260 — produced a concentrated window of civic issues across the eastern provinces, Nicaea among them. After 260, civic bronzes struck for both names simultaneously ceased, making the joint attribution a reliable bracket for dating.