Æ18 - Antoninus Pius L ΔΕΚΑΤ

The "L ΔΕΚΑΤ" reverse inscription marks this as a year-dating piece from Regnal Year 10 of Antoninus Pius — a dating convention unique to Alexandrian civic coinage, where the Egyptian calendar year was recorded directly on the bronze rather than inferred from titulature. Alexandria's mint operated under close imperial supervision but retained these local administrative conventions throughout the provincial series.

Year 10 falls within a period of notable administrative stability in Egypt, with no major disruptions to the Nile flood cycle or provincial governance recorded for 146–147 CE.