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. Two horsemen dueling with pistols, one seen from behind riding towards the left, one riding towards right, from "Various cavalry exercises" (Diverses exercices de cavalerie), ca. 1642–45. The Metropolitan Museum of Art.