Penny - Offa Heavy coinage

Offa's decision to introduce a heavier penny standard — roughly doubling the weight of earlier issues — was almost certainly tied to Charlemagne's monetary reform of 793–794, which standardized the Frankish denier at approximately 1.7g. Cross-Channel trade demanded parity, and Offa, who had negotiated directly with Charlemagne over merchant rights and the movement of pilgrims, had every commercial reason to align Mercian silver with continental weight norms. The two rulers famously fell out over a proposed dynastic marriage, briefly suspending trade entirely.

North 319 encompasses several distinct moneyer attributions, and the specific moneyer on any given specimen materially affects its rarity.