Double with ermine - John V Nantes

John V ruled Brittany through a period of calculated neutrality during the Hundred Years' War, extracting concessions from both France and England while maintaining effective independence. His monetary output was prolific by ducal standards, and the Double with ermine belongs to a series of billon issues designed to support everyday commerce at a moment when war-disrupted trade had badly degraded the small-change supply across western France.

The ermine — Brittany's heraldic marker of dynastic identity — was a deliberate assertion of separation from the French royal monetary system at a time when the Valois crown was aggressively reasserting control over feudal mints.