A formal 1659 portrait engraving by Robert Nanteuil, depicting Pierre Séguier, Marquis de Saint-Brison, in armour with a decorative heraldic cartouche.

Robert Nanteuil was a master of the portrait engraving during the reign of Louis XIV. This work, dated 1659, depicts Pierre Séguier, Marquis de Saint-Brison, in a formal oval frame. Nanteuil was known for his ability to capture the likeness of the French aristocracy with precision, often working from life, as indicated by the inscription 'ad vivum' on the plate.

The subject is shown in three-quarter profile, wearing the elaborate periwig characteristic of the mid-seventeenth century. His attire includes a lace cravat and polished armour, which denotes his status and military role. The engraving technique demonstrates Nanteuil's command of line and tone, using varied hatching to create the texture of the hair, the sheen of the metal, and the soft shadows of the face. The oval frame is inscribed with the subject's titles, providing a clear identification of the sitter within the social hierarchy of the period.

Below the portrait, a decorative cartouche features the coat of arms of the Marquis de Saint-Brison, supported by two putti. This heraldic element adds a layer of formality to the composition, typical of high-status portraiture of the era. Nanteuil's work was highly regarded for its psychological depth and technical refinement, making him the preferred engraver for the royal court. This print offers a clear example of the formal portrait style that defined the visual culture of the French Baroque. The clarity of the lines and the balanced composition reflect the disciplined approach Nanteuil brought to his craft, ensuring that the sitter's features remained the primary focus while maintaining the decorative requirements of the genre.