Tetradrachm

Byzantion's tetradrachms from this period were struck under the shadow of near-constant pressure from both the Thracian interior and competing Greek maritime powers. The city's exceptional geographic position at the Bosphoros mouth gave it leverage to extract tolls from Black Sea grain traffic — the revenue stream that funded this coinage and made Byzantion worth fighting over for the better part of two centuries. Philip II of Macedon besieged the city in 340 BC, the event that effectively closes this series.