The blue enamel oval plaque, set with rose-cut diamonds, the largest to the centre, all inlaid against cobalt black glass, the rose gold setting tapering into a crisp knife-edge shank, ring size 7 Weight: 9.20gr.

The 1786 edition of ‘Cabinet des Modes’, a French fashion magazine, describe a fashion for “very large” rings: “a large diamond is set in the middle of an oval, rectangular, lozenge, plain squared, octagonal ‘pierre de composition’ [paste glass]” (p. 137). Designs containing “little stars” are known as ‘bague au firmament’, and designs with a large central stone (alone or adorned by smaller side stones) are called ‘bague à l'Enfantement’. According to lore, these glass-and-diamond plaque rings were designed by French jewelers to celebrate the long-awaited birth of heirs to the French throne; Marie Antoinette gave birth to the Dauphin (Louis Joseph Xavier François) in 1781 and her second son (Louis XVII) in 1785. The term ‘bague à l'Enfantement’, literally “childbirth ring”, would support this design origin tale. Furthermore, the 1786 ‘Cabinet des Modes’ article mentioned that firmament and l'Enfantement rings were a fashion “less than two years old”, which would date their design inception to c. 1784-85, neatly aligning with the period right before and after the birth of Louis XVII.

While Marie and her sons did not survive the French Revolution, Firmament and l'Enfantement rings continued to be made throughout the late 18th and 19th centuries. Several post-Revolution c. 1790s French examples in the Koch collection (cat. 962, 964, 965, 967, 968) show the same designs, but with silver shanks to reflect wartime gold scarcity. The c. 1796 portrait of Madame Catherine Bruguière by Antoine-Jean Gros shows the subject wearing a halo-less l'Enfantement ring of a similar design type as the present ring. Period design drawings (e.g. the 1786 ‘Cabinet des Modes’ engraving, V&A D.320-1899) show a wide color palette for the paste grounds; in addition to the predominate shade of royal blue, Firmament and l'Enfantement rings were made with purple, puce, green, yellow, red, and black grounds.