License, verbatimCC0
The Metropolitan Museum of Art: Open Access, Creative Commons Zero (CC0). Flagged isPublicDomain=true in the museum's own record.
Anonymous. Pope Alexander III presents Doge Ziani with standards and bugles after his defeat of Holy Roman Emperor Frederick I Barbarossa, from "Il gran Teatro di Venezia" (The great theater of Venice), ca. 1720. The Metropolitan Museum of Art.