License, verbatimCC0
The Metropolitan Museum of Art: Open Access, Creative Commons Zero (CC0). Flagged isPublicDomain=true in the museum's own record.
Giovanni Battista Naldini. Elevation of Giulio Romano's House (recto); the Ruins from the Caelius Aqueduct and Temple of Claudius in Rome (verso), ca. 1557. The Metropolitan Museum of Art.