AR23 - Antoninus Pius L ΙΔ

Year 14 of Antoninus Pius corresponds to 150–151 AD, a period of pronounced debasement in the Alexandrian billon tetradrachm series. The silver content by this point had dropped well below 20%, a slide that began under Nero and continued with little reversal through the Antonine period. Egypt's coinage remained a closed monetary system — foreign coins had to be exchanged at the border and reminted — which allowed Rome to manage the province's currency independently of the imperial silver standard.

Milne 1838 places this squarely within a well-documented sequence, and the Dattari reference confirms it as a type with reasonable survival numbers.