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).
Francesco Barbazza, after Giuseppe Palazzi. The Prima Macchina for the Chinea of 1782: The Temple of Janus Built by Numa Pompilius, 1782. National Gallery of Art, Washington.