Which opera has more parts including acts and tableaux, Le roi d'Ys or Stiffelio?
Stiffelio Stiffelio is an opera in three acts by Giuseppe Verdi, from an Italian libretto by Francesco Maria Piave. The origin of this was the novel “Le pasteur d’hommes”, by Émile Souvestre, which was published in 1838. This was adapted into the French play "Le pasteur, ou L'évangile et le foyer" by Émile Souvestre and Eugène Bourgeois. That was in turn translated into Italian by Gaetano Vestri as "Stifellius"; this formed the basis of Piave's libretto.
Vénus et Adonis Vénus et Adonis is an opera ("tragédie en musique") in a prologue and 5 acts composed by Henri Desmarets to a libretto by Jean-Baptiste Rousseau. Based on the story of Venus and Adonis in Book X of Ovid's "Metamorphoses", it was first performed by the Académie Royale de Musique at the Théâtre du Palais-Royal in Paris on 28 July 1697 with Marie Le Rochois and Louis Gaulard Dumesny in the title roles. Desmarets staged a major revival of the work with a new prologue at the court of Leopold, Duke of Lorraine in 1707. During the composer's lifetime, it was performed in Germany, Belgium, and France, but then fell into obscurity. Its first staging in modern times took place at the Opéra de Nancy on 28 April 2006.