License, verbatimCC0
The Metropolitan Museum of Art: Open Access, Creative Commons Zero (CC0). Flagged isPublicDomain=true in the museum's own record.
Battista Franco. Figure Studies: Three Sketches of Cain Killing Abel, with an Altar of Sacrifice at Center, Two Standing Women, a Hand, and a Seated Child with a Squirrel, 1510–61. The Metropolitan Museum of Art.