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. Plate 9: the Arch of Constantine to left, part of the Colosseum to right, from "Roman landscapes and ruins" (Paysages et ruines de Rome), ca. 1643–48. The Metropolitan Museum of Art.