License, verbatimCC0
The Metropolitan Museum of Art: Open Access, Creative Commons Zero (CC0). Flagged isPublicDomain=true in the museum's own record.
Hans Springinklee. The Arch in the Entryway of the Left Portal (Die Porten des Lobs); and the Outer Left Column of the Central Portal, from the Arch of Honor, proof, dated 1515, printed 1517-18, 1515. The Metropolitan Museum of Art.