Double Tournois - John IV three ermines

John IV spent much of his reign navigating between the English crown — whose military support had placed him in power during the War of Succession — and a Breton nobility increasingly hostile to foreign influence. The billon coinage of his later years reflects a duchy under financial strain, with debasement progressing steadily through the 1380s and 1390s as war costs and political obligations mounted.

The Jezierski references 306–310 indicate meaningful die variation across this type, suggesting extended production across multiple minting episodes rather than a single issue.