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. A Moorish horseman facing the left, standing and seated Turks in the middle ground, and other horsemen in the background, from 'Figures on Horseback' (Cavaliers nègres, polonais et hongrois), ca. 1651. The Metropolitan Museum of Art.