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).
Jacques Perret (author). Des Fortifications Et Artifices Architecure Et Perspective De Iacques Perret Gentilhomme Svoysien, published 1601. National Gallery of Art, Washington.