License, verbatimCC0
The Metropolitan Museum of Art: Open Access, Creative Commons Zero (CC0). Flagged isPublicDomain=true in the museum's own record.
Anonymous. View of the Capitoline Hill during Michelangelo's restoration, the equestrian monument of Marcus Aurelius in the center, from "Speculum Romanae Magnificentiae", ca. 1561–63. The Metropolitan Museum of Art.