AR25 - Antoninus Pius L ΚΒ

Year 22 of Antoninus Pius's reign, which this coin marks, fell during one of the most administratively stable periods in Roman Egypt — the prefecture of Marcus Sempronius Liberalis, who suppressed a significant revolt by Egyptian peasants (the boukoloi) in the Delta region sometime in the 150s. Alexandrian billon tetradrachms of this decade are frequently encountered with noticeably variable silver content, reflecting the gradual debasement that had been creeping through the Egyptian monetary system since Nero's reforms of 64 AD.

Milne 2300 places this squarely within a well-documented die sequence at the Alexandria mint.