Year 13 of Antoninus Pius's reign fell in 149–150 AD, a period of relative administrative stability in Egypt under the prefecture. Alexandria's municipal bronze coinage operated on a distinct regnal year dating system tied to the Egyptian calendar, which is why these issues can be pinned so precisely — the year appears as part of the coin's own legend rather than reconstructed from external records. The L ΤΡΙΣΚΑΙΔ abbreviation marks it as a Year 13 piece.
Year 13 of Antoninus Pius's reign fell in 149–150 AD, a period of relative administrative stability in Egypt under the prefecture. Alexandria's municipal bronze coinage operated on a distinct regnal year dating system tied to the Egyptian calendar, which is why these issues can be pinned so precisely — the year appears as part of the coin's own legend rather than reconstructed from external records. The L ΤΡΙΣΚΑΙΔ abbreviation marks it as a Year 13 piece.