Year 25 of Commodus falls in the middle of his reign, before the increasingly erratic behavior that culminated in his assassination on New Year's Eve 192 AD. Alexandria's mint operated under tight imperial oversight during this period, producing billon tetradrachms on a near-annual basis with regnal year dating — a practice that makes sequential die studies unusually tractable for this series. The billon alloy by this point had degraded considerably from earlier Alexandrian issues, a slide in silver content that had been underway since Nero's provincial monetary reforms of 64 AD.
Year 25 of Commodus falls in the middle of his reign, before the increasingly erratic behavior that culminated in his assassination on New Year's Eve 192 AD. Alexandria's mint operated under tight imperial oversight during this period, producing billon tetradrachms on a near-annual basis with regnal year dating — a practice that makes sequential die studies unusually tractable for this series. The billon alloy by this point had degraded considerably from earlier Alexandrian issues, a slide in silver content that had been underway since Nero's provincial monetary reforms of 64 AD.