License, verbatimCC0
The Metropolitan Museum of Art: Open Access, Creative Commons Zero (CC0). Flagged isPublicDomain=true in the museum's own record.
Johann Martin von Rohden. A House near a Grotto and a Roadside Chapel at Lake Nemi, with a View of Genzano from the North; verso: Sketch of Trees on the Border of a Lake, with Mountains in the Background, early–mid 19th century. The Metropolitan Museum of Art.