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. Frieze with Tritons and Dolphins, plate 13 from "Decorative friezes and foliage" (Ornamenti di fregi e fogliami), ca. 1648. The Metropolitan Museum of Art.