Yvonne Kenny when she replaced, with only four days' notice, the soprano scheduled to sing in an Opera Rara concert performance of Donizetti's "Rosmonda d'Inghilterra" at the Queen Elizabeth Hall. It was a triumph and the virtually unknown Kenny became an overnight star. She made her debut at the Royal Opera House the following year, in the premiere of Hans Werner Henze's "We Come to the River", later singing in Handel operas such as: "Semele", "Alcina", "Giulio Cesare", and such Mozart operas as: "Idomeneo", "Mitridate, re di Ponto", "La clemenza di Tito", "The Abduction from the Seraglio", "The Magic Flute". She also
Maria Stader "The Abduction from the Seraglio", two versions (1954 and 1960) of 'Exsultate, jubilate' and the Great Mass, as well as Verdi's Messa da Requiem. She won, the Geneva International Music Competition in 1939, but although she "seemed poised for major stardom... her career was delayed by the outbreak of World War II," according to "Opera News". Later in her career, Stader acquired a reputation as an outstanding Bach interpreter, especially with Karl Richter and Ferenc Fricsay. She recorded the "Requiem" by Antonín Dvořák with Karel Ančerl, and Beethoven's opera "Fidelio" (as Marzelline) with Hans Knappertsbusch. Stader was highly praised for