Overture from the opera "Le roi d'Ys" ("The King of Ys") Overture from the opera "Le roi d'Ys" ("The King of Ys") composer Édouard Lalo Main opus "Le roi d'Ys" ("The King of Ys"), opera in 3 acts and 5 pictures, libretto by Edouard Blau based on Breton legends