Hildegard Rütgers 1963. Between 1963 and 1965 she performed at the Salzburg Festival, the part of "Die Vertraute" (Her confidante) in a production of "Elektra" by Richard Strauss, conducted by Herbert von Karajan, alongside Astrid Varnay in the title role, and Martha Mödl, Hildegard Hillebrecht, James King and Eberhard Waechter in leading parts. The production of Mozart's "Die Zauberflöte" at the Salzburg Festival, with Rütgers as the Third Boy, was filmed and released as a made-for-television-movie in 1964. She appeared alongside Walter Kreppel as Sarastro, Roberta Peters as the Queen of the Night, Pilar Lorengar and Waldemar Kmentt as Pamina and Tamino,
Mozart and dance eighteenth-century composers were expected to be adept at producing both 'popular' and 'serious' music, and that there was no categorical difference between the two.". Abert (2007) wrote, "the most striking aspect of these dances is their almost literally inexhaustible fund of invention. Although their form offers only limited scope for experimentation, each dance differs from the others." Lindmayr-Brandl (2006) writes that "[the dances] that are accessible today, brought to life in the concert hall or in recordings, represent a precious treasure, the immediate expression of the joy of life." Mozart included a substantial ballet at the end of his opera