Both cover plates are in fact the result of the pairing of external and internal metal foils. The external plates, made of embossed, blued and mercury-gilded foil, have moulded edges on three sides and feature two finely decorated oval reliefs nailed to the main plaque: the first oval depicts Artemisia raising a cup with the ashes of her husband Mausolus dissolved in her tears, surrounded by a dog and an ermine, the other oval depicts Cleopatra committing suicide with the Asp, flanked by a cherub and a sphinx.

The inner sides of the cover are decorated with two polished steel plates, finely engraved with vegetal scrolls, framing two oval plaquettes inscribed in gilded capital letters over blued iron with these two mottoes: “LE PLUS BEAU EST CACHÉ” and “VOUS NE CONNOISSES PAS TOUS MES SECRETS”.

This extraordinary Artwork is a compendium of all the most sophisticated ironworking techniques: - embossing, engraving, gilding and blueing - typically applied to arms and armours and for this reason the piece was most likely made by an important French armourer for a high-ranking person.