The broad, shallow bowl of this wine cup is a borrowing into silver design of a Venetian glass form popular in the second half of the sixteenth century. Although few glass examples survive, we know of their use from Italian paintings, in which typically a dimpled ground in the bowl served to enhance the sparkling, light-filled character of the wine.
Cruising serenely through little wavelets, the swan at the center of this bowl is an emblem of the Vintners' Corporation, the guild for men active in the wine trade whose responsibilities included monitoring conditions on the docks and securing honest trading. The Vintners' Corporation, one of the earliest guilds, received a charter in 1364. The four marks which seem to disfigure the side of the cup are in fact hallmarks, struck at the Hall of the Goldsmiths' Company, which regulated gold- and silversmiths and guaranteed the quality of the sterling stand and metal. The marks indicate year and place of manufacture as well as the maker or his workshop. The maker's mark on this tazza has not been identified.
Marking:  Leopard’s head crowned (London assay office mark)  lion passant guardant (English quality mark for sterling)  possibly capital M with line across possibly  Capital B in pointed shield (London date letter)
Location of marks: – On outer lip of bowl
Lord Tredegar (until 1957; sale, Sotheby's, January 24, 1957, no. 136) ; [ S. J. Phillips Ltd. , 1957; sold March 13, 1957 to Irwin Untermyer ] ; Irwin Untermyer (1957–68; to MMA)
Artist: James Cox (British, ca. 1723–1800)Date: 1766Medium: Case: gold with diamonds and paste jewels set in silver, pearls; Dial: while enamel; Movement: partly gilded brass and steel, wheel balance and cock of silver set with paste jewelsAccession: 1982.60.137On view in:Gallery 540