2½ ECU - Beatrix Christiaan and Constantijn Huygens

This issue commemorates Constantijn Huygens the Younger, son of the more famous poet and statesman of the same name, who served as secretary to William III and kept one of the most detailed personal diaries in Dutch Golden Age history. The ECU denomination itself was a product of the European Monetary System established in 1979 — not legal tender in the conventional sense, but issued by several member states as collector and quasi-currency pieces throughout the 1980s and into the 1990s.

The X# catalog prefix signals its status outside standard national coinage, catalogued by Krause under their Unusual World Coins reference rather than the primary listings.