License, verbatimCC0
The Metropolitan Museum of Art: Open Access, Creative Commons Zero (CC0). Flagged isPublicDomain=true in the museum's own record.
Albrecht Altdorfer. Maximilian's Prowess in the Chase; and The Legend of the Holy Coat of Treves; with Portraits of Emperors and Kings (Maximilian's Forerunners), from the Arch of Honor, proof, dated 1515, printed 1517-18, 1517/1518. The Metropolitan Museum of Art.