But easily overlooked until last year, it would seem. It then appeared in a Left Bank gallery in Paris, where it certainly did not attract museum attention. The Louvre could have stopped it from leaving France. Probably not the latter. The knowledgeable Louvre curators would have recognized the image.
Indifference is the likely answer.
That saved the day for Daniel Katz of London who bought it from his Paris colleague, who had no trouble getting an export license. Katz got the remarkable art historian Johannes von Auersperg, who works for him, to identify the sitter beyond any doubt and published the bust in the catalogue, which came out in April. This time the museum world reacted. The Prado, alerted to the existence of the bust by Katz, expressed interest. Its appearance in the selling show put up by the dealer on his London premises in Jermyn Street, where it opened on June 8, set the wheels rolling.