AR22 - Valerian and Gallienus L Α

This joint issue marks the opening of Valerian and Gallienus's co-regency, with Valerian taking the East and Gallienus administering the West — a division that would calcify into permanent structural fracture within a decade. The Alexandrian mint under Roman administration had long produced its own billon tetradrachms on a closed currency system, meaning Egyptian coins could not legally circulate outside the province, nor foreign coins within it. The L Α regnal date places this firmly in the first Egyptian year of their reign.