Denier - Charlemagne Rouen

Charlemagne's monetary reform of c. 793–794, enacted through the Capitulary of Frankfurt, replaced the lighter Merovingian denier with a heavier silver standard — the same reform that established the pound-shilling-penny accounting system Europe would use for the next millennium. Rouen, as the administrative capital of Neustria and a major Loire trade hub, was among the active minting centers under this reorganization.

The Prou reference absence is worth noting: Prou's catalogue gaps for certain Carolingian mint attributions are well documented, and the Depeyroux number here carries the weight of the attribution.