License, verbatimPD
The National Gallery of Art: open access image with no usage restrictions under the NGA's open access policy (openaccess=1 in the Gallery's published_images dataset).
Miguel de Sorellò, after Pierre Parrocel, after Michelangelo Specchi. The Prima Macchina for the Chinea of 1739: Mount Parnassus with Apollo, the Muses, and Pegasus, 1739. National Gallery of Art, Washington.