Tetradrachm - Nero ΑYΤΟΚΡΑ, Alexandria

This issue belongs to the tenth year of Nero's reign, struck at the imperial mint in Alexandria — the only mint permitted to produce coinage for Egypt, which Rome administered as a personal imperial province deliberately kept off-limits to senators. The Alexandrian billon tetradrachm functioned as a closed currency system; it could not legally circulate outside Egypt, and foreign coins brought into the province were exchanged at the mint, giving Rome a quiet but consistent profit on the exchange.

Year 11 of Nero's reign, which this piece dates to, preceded the great fire of Rome by a matter of months.