This week in La Gazette Drouot: A Roman cameo by Emperor Claudius: from Antiquity to the 19th century, the story of a masterpiece

Some objects you only come across once in your career ," says auctioneer Alexandre Baron-Reverdito. And that meeting took place in a Paris apartment, during an inventory for a family not quite like any other, since it descended from Baron Alfred Octave Roger de Sivry (1806-1874), son of the collector Salomon Louis Roger (1765-1841), a Geneva-born banker who became Baron d'Empire in 1810.

Antoine Tarantino was struck by this precision, as the after-death sale of Baroness Roger de Sivry - held on April 18 and 19, 1904 at Drouot - was a benchmark in the cameo field. The expert in classical archaeology, who for years had been in possession of a photo version of this rare catalog, discovered not only the reproduced cameo, but also an unexpected handwritten note stating that Vivant Denon had claimed in his time that the object was one of those offered to Napoleon I by Pius VI, following the 1797 Treaty of Tolentino.

This information prompted the family to withdraw the object from the sale. Although this imperial - and even papal - provenance remains a hypothesis, it seems plausible, as the baron was perfectly eligible for a gift from the Emperor - he was one of the twenty merchants who financially supported his ascension from the outset.