Which opera, if any,  Venus and Adonis or Bluebeard's Castle has more acts ?
Bluebeard's Castle Bluebeard's Castle (Hungarian: A kékszakállú herceg vára ; literally: "The Blue-Bearded Duke's Castle") is a one-act 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 ("Kékszakállú "), and his new wife Judith ("Judit " ); the two have just eloped and Judith is coming home to Bluebeard's castle for the first time.
Fair Rosamond (opera) Fair Rosamond is an English historical opera in four acts composed by John Barnett, written in 1837 to a libretto by Charles Zachary Barnett, after the legend of Rosamund Clifford ("Fair Rosamond" or the "Rose of the World"), the 12th century mistress of King Henry II who was said to have been poisoned by the King's wife, Queen Eleanor. In his opera, Barnett effects a happier ending.