Michel Sittow, a northern painter who was born in Estonia on the Baltic Sea but apprenticed in Bruges, was an acclaimed portraitist at the Spanish court. After Queen Isabella's death in 1504, his peripatetic career took him to several northern European centers, including Burgundy, where he probably painted this portrait.
The sitter gazes with serious mien, not at the viewer, but at an unseen point beyond the picture's frame. The ornate carpet covering the stone parapet on which his hand rests provided scholars with an important clue that led to the discovery of the object of his concentration -- a painting of the Madonna and Child, of similar dimensions, in the Gemäldegalerie in Berlin. In that panel a larger portion of the parapet, covered by the same carpet, appears as a support for the Christ Child. It seems certain that the Berlin and Washington panels were originally hinged together to form a devotional diptych.
Circumstantial evidence suggests that the National Gallery's portrait represents Diego de Guevara, a nobleman whose family came from Santander in northern Spain. For forty years Don Diego was a valued member of the Habsburg court in Burgundy. Supporting this identity is the embroidered cross of the Spanish Order of Calatrava on his golden doublet; after serving in numerous positions of trust in the households of Philip the Fair and Charles V, Don Diego was appointed to the wardenship of that order.