William BOUGUEREAU signed autograph carte de visite Iron Mask painting

  

Who is the Man in the Iron Mask? "With a thousand thanks for the kind manner in which Mr. Le Masque de Fer shares his appointment to the Institute." Is it the painter and engraver Célestin Nanteuil, appointed in 1867 as director of the Academy of Fine Arts, who signed an illustration of The Man in the Iron Mask in his prison?