License, verbatimCC0
The Metropolitan Museum of Art: Open Access, Creative Commons Zero (CC0). Flagged isPublicDomain=true in the museum's own record.
Stefano della Bella. The Colosseum, two herds being directed towards the amphitheater in the foreground, plate 8 from "Roman landscapes and ruins" (Paysages et ruines de Rome), ca. 1646. The Metropolitan Museum of Art.