The valuable collection of drawings at the National Library of Spain is noted for the high quality of its Italian drawings spanning the 16th century to 19th century. This architectural drawing, which follows baroque conventions, is a self-portrait of Giovanni Battista Montano (1534−1621), who is shown carrying the compass and ruler of an architect. The allegories of Architecture and Geometry are seen at each side. The drawing was conceived as a frontispiece for Montano’s unpublished treatise, in which he interpreted the works of such architects as Palladio and Vignola and drew upon the other major source of architectural knowledge at the time, the ruins of classical antiquity. The contemporary scholar Delfín Rodríguez has shown that Montano’s album of 45 architectural drawings, also preserved in the National Library of Spain, was clearly influenced by Vignola and Palladio. In his day Montano was considered a fine sculptor in wood, an essayist, and an architectural draftsman. His engravings of Roman architectural ruins were a major influence on Borromini and Bernini. Montano was a member of the prestigious Accademia di San Luca, founded to serve the educational and professional needs of architects, painters, and sculptors in Rome, and was partially responsible for the design of the academy’s church. His drawings are now dispersed among many different European libraries.