AR23 - Antoninus Pius L ΙΕ

Year 15 of Antoninus Pius's reign, which this coin's regnal date marks, fell during one of the most administratively stable periods in Roman Egypt — no revolt, no currency crisis, just the machinery of the Alexandrian mint grinding through its annual tetradrachm production. The billon content of these issues had been quietly declining since the early empire, a process of slow debasement that accelerated markedly under later reigns.

Alexandria operated under a closed currency system: Roman provincial coins could not circulate freely into Egypt, nor Egyptian issues out. Every coin entering the province was reminted at a profit to the imperial treasury.