Robert Nanteuil made this pastel portrait of Louis Doni d'Attichy, the Bishop of Riez and later of Autun, as a preparatory study for an engraving made in 1663 . Scholars believe that the print was intended to adorn the cover of a doctoral thesis dedicated to the eminent bishop. Broadly defining the sitter's garments and leaving the background plain, Nanteuil concentrated on modeling the facial features with the utmost precision, giving the illusion of rendering the sitter with exacting realism.