An ivory and mother of pearl mounted wooden tryptych, possibly Dieppe, the central panel depicting Frederick II of Prussia and Voltaire strolling together in a grand hall, the hinged side panels displaying a single portrait of each man in oval frame. the surrounding field in mother-of-pearl decorated with scrolling foliate and mask head motifs, and similarly decorated borders alternatiing with narrow iridescent mother-of-pearl bands, the outer border comprising ivory panels with interlocking rope patterns in relief and with rosettes to corners, 41 cm high, 63 cm wide (open)