Philip I's Alexandrian coinage belongs to the provincial series administered through the Roman prefect of Egypt, where regnal years rather than consular dates governed the mint's output. Year 4 of Philip's reign — marked by the Δ — corresponds to 246–247 AD, placing this issue squarely between his Danubian campaigns and the celebrated Secular Games of 248 AD, which Philip staged to mark Rome's thousandth anniversary. The Alexandrian mint remained one of the few provincial operations still producing billon tetradrachms at this period, a closed currency system that prevented Egyptian coinage from circulating outside the province.
Philip I's Alexandrian coinage belongs to the provincial series administered through the Roman prefect of Egypt, where regnal years rather than consular dates governed the mint's output. Year 4 of Philip's reign — marked by the Δ — corresponds to 246–247 AD, placing this issue squarely between his Danubian campaigns and the celebrated Secular Games of 248 AD, which Philip staged to mark Rome's thousandth anniversary. The Alexandrian mint remained one of the few provincial operations still producing billon tetradrachms at this period, a closed currency system that prevented Egyptian coinage from circulating outside the province.