 Among her most celebrated performances during this period was an assumption of Isolde's role in a famous production of "Tristan und Isolde" mounted under Mahler's leadership.Away from Vienna, von Mildenburg sang to acclaim in London at The Royal Opera House, Covent Garden, performing Isolde and Elizabeth in "Tannhäuser" there in 1906, as well as Klytemnestra in the first London production of Richard Strauss' "Elektra".Her repertoire was not confined, however, to works by Strauss and Wagner.