Æ25 - Valerian and Gallienus ΝΙΚΑΙΕΩΝ

Nicaea's civic bronze coinage under the joint reign of Valerian I and Gallienus reflects the administrative peculiarity of that period — a formal co-emperorship in which the senior Augustus controlled the East while Gallienus managed the West, leaving provincial mints like Nicaea operating under a dual imperial authority that would dissolve with Valerian's catastrophic capture by Shapur I at the Battle of Edessa in 260 AD. After that capture, Nicaea's allegiance shifted entirely to Gallienus, making coins naming both rulers dateable to before 260.