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, which was, according to the legend, the capital of the kingdom of Cornouaille. It premiered at the Opéra Comique in Paris on 7 May 1888. Apart from the overture, the most famous piece in the opera is the tenor's aubade in act 3, "Vainement, ma bien-aimée" ("In vain, my beloved").
Lalo composed Le roi d'Ys between 1875 and 1878 (drafting the entire opera, in its first version, in 1875). His interest in the folklore of Brittany was prompted by his wife, the contralto Julie de Maligny, who was of Breton origin. The role of Margared was originally written for her. Getting the opera staged proved difficult, however. It was turned down by the Théâtre Lyrique in 1878, and by the Opéra de Paris in 1879, although extracts were heard in a concert with Julie as Margared. Lalo undertook a revision of the work in 1886, and it was finally premiered by the Opéra-Comique in the Salle du Châtelet, Paris, on 7 May 1888 to great success. Within a year of its premiere, Le roi d'Ys had reached its 100th performance there.