License, verbatimCC0
The Metropolitan Museum of Art: Open Access, Creative Commons Zero (CC0). Flagged isPublicDomain=true in the museum's own record.
Anonymous, French, 16th century. Unknown, portal or niche, plan and elevation; perspective study, interior, square chamber with cross-vault, with a scale figure (recto); blank (verso), early to mid-16th century. The Metropolitan Museum of Art.