Charles Towneley was a collector of ancient art, best known for acquiring the famous chalice of Abbot Suger of Saint-Denis. The chalice, now in the NGA, with its ancient sardonyx cup, had been stolen in February of 1804 from the Cabinet National des Médailles et Antiques, Paris, and smuggled inside a plaster bust of Laocoön to England. Towneley's collection passed to the British Museum, but Suger's chalice remained with the family until sometime between 1880 and 1920, when it was sold at a public auction.
Mersan, Marion du. Histoire du cabinet des médailles, antiques et pierres gravées. Paris, 1838: 177.