Not That long ago, I saw a, shall we say, underattributed denier on French ebay. Nabbed it. Denier of Bayeux, anon. c. (?) mid-late 10th c.; immobilized from later (...and very common) 'GDR' issues of Charles II, le Chauve /the Bald. The pics, from the original listing, start with the reverse; I'm running with it. Rev. +IAIOCASH CITAS. ([Blundered Medieval Latin for 'Bayeux'] civitas.) Obv. 'KAROLVS' monogram; (From 10 o'clock: ) +CPATIA D-I REX. [Blundered version of 'GRATIA D-I REX'; Gratia Dei Rex.] I'm not as good at this as other people, but this might be a die match of Dumas, Le Tresor de Fecamp, no. 6047 (pp. 104-5 and pl. VI). See also Moesgaard's article, "A Survey of Coin Production and Currency in Normandy, 864-945," in Graham-Campbell et al., eds., Silver Economy in the Viking Age (2007), 99-121, esp. pp. 104-5 and Fig. 6.3.) It's very light, and viscerally crappier silver than you'd expect from an official Carolingian issue. After that, I 'had' to find an example of the Carolingian prototype. That took some old-fashioned good luck. Denier of Charles II /the Bald (grandson of Charlemagne) as king of (West/) Francia; post-Edict of Pitres / 'GDR' issue, c. 864-875. Rev. Cross; +HBAIOCAS CIVITAS. (Right, especially for place names, the Medieval Latin orthography can be a hoot. Sit back, and enjoy the ride....) Obv. 'KAROLVS' monogram. [From 9 o'clock:] +GRATIA.D-I.REX. Back ...yeah, kind of inexorably... to the Norman immobilization, available evidence seems to suggest that it's no later than the reign (sorry, comital, not ducal) of Richard I (942-996), but with origins predating the issues of Rouen in his own name. (...And later; after all --drum-roll, please-- it's an immobilization.) Dunbabin, France in the Making: 843-1180 (1985, with one second edition; Find it!!) makes a prescient numismatic reference to this, with resonant historical context (pp. 80-1). Among other academic historians, Bates notes Bayeux as the second and much less active of the first two Norman mints. (Normandy Before 1066, pp. 128-9.) It's fun to see how this anticipates the first, no less ad hoc minting efforts of the Normans in Apulia and Calabria, a century and change later.