Blanca - Enrique IV diamond, Coruña

Enrique IV's monetary policies were among the most chaotic in Castilian history. The proliferation of mints operating under private or semi-private licenses during his reign produced a currency so debased and inconsistently struck that the Cortes repeatedly demanded reform, ultimately forcing the 1471 ordinances that attempted to consolidate authorized minting locations — La Coruña among them. The diamond-shaped countermark on pieces from this period was introduced specifically to certify validity amid widespread rejection of royal coin by merchants and local markets.

AB#830 is a notoriously variable type; weight and alloy consistency across surviving specimens suggest the Coruña facility operated near the margins of even the relaxed tolerances of the era's reform edicts.