THRACE. Byzantion. Countermarked on a Tetradrachm in the name and types of Alexander III 'the Great' (336-323 BC)
Obv: Head of Herakles right, wearing lion skin; c/m: prow of galley right, BY above, within circular incuse. Rev: AΛΕΞΑΝΔΡΟΥ. Zeus seated left on throne, holding eagle and sceptre; uncertain controls. . Condition: Fair. Weight: 16.71 g. Diameter: 27 mm.