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. Plate 4: five grotesque heads, from "Friezes, foliage, and grotesques" (Frises, feuillages et grotesques), ca. 1642–43. The Metropolitan Museum of Art.