Tetrachalkon Aigion

The Achaean League's bronze coinage represents one of the ancient world's more deliberate experiments in federal monetary policy — member cities retained local issues but the League imposed a unified federal coinage for common transactions. Aigion served as the League's administrative headquarters, where the synedrion met, giving coins struck there a functional role beyond ordinary commerce.

The 146 BC terminal date marks the Roman destruction of Corinth and the League's dissolution by Lucius Mummius, after which Greek federal coinage of this type ceased entirely.