The monogram is for Anatoly Demidoff (1812-70), the Russian and French industrialist, who was also the first prince of San Donato.
Demidoff was a patron of Romantic artists such as Paul Delaroche and Eugène Delacroix and one of the top clients of renowned Parisian jeweller Chaumet. In 1840 he married Princess Matilde Bonaparte, daughter of Girolamo Bonaparte.
The union was stormy and lasted only six years but Demidoff remained a Napoleonic devotee. In 1851 he bought the villa of San Martino on the island of Elba and built a museum there – today called the Demidoff Gallery.
This locket, c.1860, with its spectacular guilloche enamel decoration and natural saltwater pearl drop, is in the manner of the illustrious Parisian firm Falize.
It has the Latin legends Ei Quoad Vixit Una Fides Unus Amor (For him lived one faith one love) and Dimi Cavit Verbo et Ense (By the word and the sword).
Offered in its original case at Wannenes in Monaco on January 18, it was estimated at €4500-5500 but sold at €40,000 (£34,800), plus 30/25% buyer’s premium.