AR23 - Antoninus Pius L Ε

Alexandria's billon tetradrachms under Antoninus Pius were struck by the Roman provincial administration using a deliberately debased silver alloy — the Egyptian coinage system remained deliberately isolated from the imperial silver denarius, preventing currency arbitrage between the province and Rome. The regnal year Ε (year 5, 141–142 AD) falls squarely within a period of administrative stability in Egypt, with no known monetary disruptions specific to this issue.

The Dattari collection, from which Savio later produced the revised corpus, remains the foundational reference for Alexandrian tetradrachms; many specimens Dattari personally excavated from Egyptian sites in the late 19th century.