AR24 - Antoninus Pius L ΚΓ

Year 23 of Antoninus Pius's reign, recorded in the dating formula as L ΚΓ, places this tetradrachm in what proved to be the emperor's final regnal year — he died in March 161 AD. The Alexandrian mint under Roman rule operated on its own closed currency system, meaning these billon tetradrachms could not legally circulate outside Egypt, a deliberate fiscal mechanism that kept provincial coinage quarantined from the broader imperial economy.

Dattari's numbering for this type derives from his landmark 1901 Cairo collection catalog, still the foundational reference for Alexandrian imperial coinage despite being over a century old.