Question: Léontine de Maësen (15 July 1835 – 1906) was a Belgian coloratura soprano active on the opera stages of France from 1858 to 1868, most remembered today for having created the role of Leïla in Bizet's 1863 opera in three acts, titled what?
Sentence (from "Anna Deinet"): She is best remembered today for portraying Brangäne in the world premiere of Richard Wagner's "Tristan und Isolde" in 1865 and Helmwige in the premiere of Wagner's "Die Walküre" in 1869.
Relevant evidence: No