AR24 - Antoninus Pius L ΙΔ

Year 14 of Antoninus Pius — regnal year 14 corresponds to 150/151 AD — places this tetradrachm squarely within the most administratively stable period of Roman Egypt. The Alexandria mint operated under strict prefectural control, producing billon tetradrachms as the province's sole fiduciary currency, deliberately isolated from the broader Roman monetary system. Egypt's coinage remained a closed currency circuit: foreign coins had to be exchanged at the border, and Alexandrian issues could not legally circulate outside the province.

The billon content of Alexandrian tetradrachms was already degrading noticeably by Pius's reign, a process that would accelerate sharply under his successors.