Æ23 - Antoninus Pius L ΔΕΚΑΤΟΥ

The date inscription L ΔΕΚΑΤΟΥ — "year ten" — places this issue in the tenth regnal year of Antoninus Pius as counted by the Alexandrian calendar, a dating system independent of Rome that began each year on the first of Thoth. Alexandria's civic bronze ran on this local reckoning throughout the imperial period, which makes Egyptian provincials among the most precisely datable of all Roman-era issues. The mint was prolific in this reign; Antoninus Pius governed so uneventfully that Egypt saw none of the emergency production pressures that distort other series.