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. Moorish horseman in profile facing right, a black slave holding a fur at right, another horseman to left in the background, from 'Figures on Horseback' (Cavaliers nègres, polonais et hongrois), ca. 1651. The Metropolitan Museum of Art.