The circumstances involving the commission are not known. Until 1896 the work Portrait if Duke of Pastrana belonged to the collection of the dukes of Osuna, an aristocratic family of Castile, whom Quevedo paid tribute to in his Immortal Memory of Don Pedro Girón, Duke of Osuna, who Died in Prison. Members of the Osuna family were painted by Goya, almost two centuries later, in the famous family portrait, currently at the Prado. A distinguished member of the Court of Charles II, fourth duke of Pastrana is the most important title of Don Gregorio de Silva Mendoza y Sandoval y de Estremera, prince of Melito and of Eboli, count of Saldaña, Knight of Santiago and of the Order of the Golden Fleece. Carreño makes at least one more portrait of him, currently at the Prado, unanimously considered his master-piece in the genre. In terms of style, the two portraits are far removed. Unlike the Madrid portrait, extremely close to the manner of Van Dyck, the painting on display at Masp boasts a stricter Castilian culture, also more conventional, and the intervention of the workshop in smaller parts of the figure cannot be discarded. The portrait preserved at Masp most certainly preceded the one at the Prado, as evidenced by the more youthful appearance of the subject, probably dating back to the artist’s first years as Court painter, after 1665. Also unlike the one at the Prado, this is a chamber portrait, displaying a pompous scenery, entirely created in crimson hues and supported chiefly by the development of a massive set of curtains, with a bulky pendant, and by sumptuous objects, as the oddly looking object that rises from the table, perhaps an indication of the subject’s “studiolo” fancy for collecting objects, a symbol of Don Gregorio’s aristocratic background. The focus of the artist when composing the subject is directed to the meticulous shaping of this structure with external attributes, but nevertheless more important in the development of the character of the subject than any facial feature or expression, trait of disposition, or psychological quality.
— Unknown authorship, 1998