20 Pesetas Luis de Haro

Pheasant Island — the half-hectare river island in the Bidasoa jointly administered by France and Spain in alternating six-month periods — is almost certainly the world's smallest condominium territory and one of the strangest jurisdictions in Europe. The arrangement dates to the 1659 Treaty of the Pyrenees, negotiated largely by Luis de Haro on the Spanish side. That this numismatic curiosity invokes his name is fitting, since the island itself exists as a direct consequence of his diplomacy.