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,
Vienna Mozart Orchestra world-famous opera houses, principally from the Vienna State Opera and the Vienna Volksoper, perform with the Vienna Mozart Orchestra. Best-known and most popular is the concert series “Vienna Mozart Concerts in historical costumes”, performed every year from May until the end of October, four times a week. An ideal background for these concerts is provided by the Golden Hall of the Musikverein, the Vienna State Opera and by the Great Hall of the Konzerthaus (each about 40 concerts a year). As a co-production with Klangbogen Wien within the framework of the Millennium celebrations in 1996, ten open-air concerts were performed