"Bluebeard's Castle" (; literally: "The Blue-Bearded Duke's Castle") is a one-act expressionist opera by Hungarian composer Béla Bartók. The libretto was written by Béla Balázs, a poet and friend of the composer, and is written in Hungarian, based on the French literary tale "La Barbe bleue" by Charles Perrault. The opera lasts only a little over an hour and there are only two singing characters onstage: Bluebeard (), and his new wife Judith (); the two have just eloped and Judith is coming home to Bluebeard's castle for the first time.