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.
Les petits riens Les petits riens ("The Little Nothings"; the lowercase in the original title is authentic) was a ballet in one act and three tableaux by Jean-Georges Noverre, with music by Wolfgang Amadeus Mozart, created at the Academie Royale de Music in Paris on 11 June 1778.