The viola da gamba played by Myrna Herzog is an important instrument made by Andrea Castagneri in 1744. It is labelled Andrea Castagneri nell Pallazzo di Schoessone, Pariggi 1744.
It is very similar to the instrument played by M. Pitoin in the watercolor "Mademoiselle Pitoin à son piano, Monsieur Son Père l'accompagnant à la basse" by Louis Carrogis, dit CarmontelleE (1717-1806).
There is an extensive article tbout the Castagneri viol, illustrated with photos, at the "History of the Parisian violin making from the XVIIIth century to 1960” by Sylvette Milliot (Paris 1997).
Andréa Castagneri (1696-1747) was born in Italy, and moved to France around 1720 as a servant of the Prince of Carignan, settling with his wife in the Prince's residence, the Palace of Soissons (where this viola da gamba was made). He learned the violin-making profession in Paris, receiving his diploma in 1740. After the death of the Prince in 1741, Castagneri earned his life as a luthier. His clients were the most important professional players, and the most aristocratic amateurs.
Andrea Castagneri is considered one of the most important French string instrument makers. The Encyclopédie Méthodique (Paris 1785) in its chapter on the violin (p.24) says: “Among the makers established in France, we distinguish Boquet, Pierray, Castagnery & others, who have made violins comparable to the most celebrated makers which we just named [Amati, Stradivarius, Steiner].”