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).
Domenico Quaglio. Ruine Frauenkirch mit dem Grabmale der Genoveva und des Pfalzgrafen Siegfried (Ruins of the Church of Our Lady with the Tombs of Genevieve and Count Siegfried), 1821. National Gallery of Art, Washington.