AR18 - Diocletian L ΕΝΑΤΟΥ, Β

Year nine of Diocletian's reign in Alexandria corresponds almost exactly to his monetary reform of 293–294, in which the empire-wide currency overhaul — part of the broader reorganization accompanying the establishment of the Tetrarchy — disrupted Alexandrian mint output significantly. Egypt had maintained a closed currency system since the Ptolemaic period, meaning Roman coins did not circulate there and Alexandrian issues did not leave; this billon tetradrachm is a product of that system's final years before Diocletian forcibly ended it, integrating Egypt into the imperial monetary network.