Durango issued copper fractional coinage during the 1860s largely because the federal government in Mexico City had effectively lost the ability to enforce monetary uniformity — the Reform War and the French Intervention had shattered central authority, leaving individual states to fill the gap in small-denomination currency however they could. The quartilla existed to serve daily market transactions that silver simply couldn't reach at practical scales.
KM#349 is specific to 1866, a year in which Maximilian's imperial administration was already visibly faltering, with French troop withdrawals imminent following U.S. pressure after the end of the Civil War.
Durango issued copper fractional coinage during the 1860s largely because the federal government in Mexico City had effectively lost the ability to enforce monetary uniformity — the Reform War and the French Intervention had shattered central authority, leaving individual states to fill the gap in small-denomination currency however they could. The quartilla existed to serve daily market transactions that silver simply couldn't reach at practical scales.
KM#349 is specific to 1866, a year in which Maximilian's imperial administration was already visibly faltering, with French troop withdrawals imminent following U.S. pressure after the end of the Civil War.