20 Euro Centenary gold coinage San Marino

San Marino has issued commemorative gold coinage under a long-standing agreement with Italy, which has administered the republic's monetary relationship since the lira era and continues under the euro framework through a specific convention with the EU — one San Marino negotiated independently, despite not being an EU member state. Annual allocations are tightly capped, keeping mintages well below those of any eurozone sovereign.

The .999 fineness here is notably purer than the .900 gold standard common to most 20th-century European gold coinage.