Question: Le roi d'Ys and Serse, is which type of play?
Sentence (from "Le roi d'Ys"): Le roi d'Ys ("The King of Ys") is an opera in three acts and five tableaux by the French composer Édouard Lalo, to a libretto by Édouard Blau, based on the old Breton legend of the drowned city of Ys.
Relevant evidence: Yes