Rectangular, on ivory, within a decorative border and a gilt-metal frame, 8.1cm.
The reverse is engraved: ‘By Mr Byres: from the mosaic dug out of the Emperor Adrian’s Villa at Tivoli; now plac’d in the Collection at the Capitol in Rome.’ Circa 1775.
James Byres, a Scottish antiquary and dealer in Old Master paintings, acquired a number of works of art for Brownlow, 9th Earl of Exeter (1725-1793), in the later 18th Century.