Denier - Louis I Rennes

This denier belongs to the monetary reform Louis the Pious implemented following the Council of Aachen in 816–817, which standardized weights and types across the Carolingian mints. Rennes, as a frontier mint serving Brittany — never fully pacified under Carolingian rule — was granted striking rights partly as a tool of political integration. The brief dating window reflects Louis's shifting administrative reorganizations of the Breton march during precisely this period.