Æ20 - Valerian and Gallienus COL AVG TRO (D)

Alexandria Troas was a Roman colony founded under Augustus and held unusual administrative autonomy that allowed it to produce its own bronze coinage well into the third century — a privilege most Asian cities lost far earlier. The joint reign of Valerian and Gallienus, 253 to 268, was defined by near-continuous military crisis: Valerian's catastrophic capture by Shapur I at the Battle of Edessa in 260 effectively ended the co-reign, making issues attributable to both emperors simultaneously a narrow window.

The Conventus of Adramyteum designation places this coin within the judicial district centered on the Troad coast.