It is an enamel of evident interest, despite its poor state of preservation and the fact that it is a fragmentary component, which makes it difficult to classify it correctly. It is round, with a dotted border, and has four holes for it to be riveted to a support. It has two diametrical gaps, at the top and bottom, doubtlessly to fix it to its original support. The decoration consists of two sirens (or bird-women) with diverging bodies, except the heads, which are facing. The ends of the tails turn into palm leaves. They flank a central, vertical axis of floral stylisations. The enamel is completely lost, and there is quite a lot of gilt, not superficial, but introduced into the areas gouged out like another layer of enamel. The catalogue of the medals and mediaeval horse trappings ornaments in the MEV (1995) draws attention to the object and suggests dissociating it from the rest of the collection, and points to the possibility of it being part of the decoration for a casket, attributing it to the same workshop as a similar Hispano-Limousin medallion in the Kunstgewerbemuseum in Cologne, an evident parallel. I would add that it could be a letter M formed by the combination of phytozoomorphic elements, as is habitual in the 'marginalia' of books in miniature, and corresponding, perhaps, to a late 12th-century Romanesque-Gothic state of transition, as has already been suggested, or to the 13th century.