License, verbatimCC0
The Metropolitan Museum of Art: Open Access, Creative Commons Zero (CC0). Flagged isPublicDomain=true in the museum's own record.
Pietro da Cortona (Pietro Berrettini). The holy trinity with Saint Michael vanquishing a six-headed dragon, frontispiece to 'Missale Romanum ex decreto sacrosancti Concilii tridentini restitutum', ca. 1662. The Metropolitan Museum of Art.