Philip IV (1605–65), who succeeded to the throne in 1621, was a weak ruler but a lavish patron of the arts and letters. He promoted the Spanish theater, built the Palacio del Buen-Retiro, enlarged the royal collections, and was Velázquez’ most ardent supporter. In 1644 Velázquez accompanied the King on a campaign to Catalonia, where the Spanish army led a successful siege of Lérida against the French. In the town of Fraga, the King’s headquarters, in a dilapidated, makeshift studio, Philip posed for this portrait dressed in the silver-and-rose costume he wore during the campaign. Although Velázquez painted numerous portraits of Philip IV, this is the only one dating from the 1640s.
Source: Art in The Frick Collection: Paintings, Sculpture, Decorative Arts, New York: Harry N. Abrams, 1996.