License, verbatimCC0
The Metropolitan Museum of Art: Open Access, Creative Commons Zero (CC0). Flagged isPublicDomain=true in the museum's own record.
José Guadalupe Posada. Cover for 'La Paloma Azul : Coleccion de Canciones Modernas Para 1901', two couples dancing while a dove flies in between them, ca. 1901. The Metropolitan Museum of Art.