License, verbatimCC0
The Metropolitan Museum of Art: Open Access, Creative Commons Zero (CC0). Flagged isPublicDomain=true in the museum's own record.
Albrecht Dürer. Maximilian as Architect; with a Statue of St. Leopold; and Busts of Maximilian's Ancestors and Relatives, from the Arch of Honor, proof, dated 1515, printed 1517-18, 1517/1518. The Metropolitan Museum of Art.