Input (grade 13): Della Casa sang the part of Zdenka in the performance of Richard Strauss' Arabella at Zurich Municipal Opera House to her revered soprano Maria Cebotari's Arabella in 1946.
Output (grade 11): In 1946 Della Casa sang the part of Zdenka in Richard Strauss's opera Arabella in ZÃ 1\/4 rich, and again the following year when she sang for the first time at the Salzburg Festival where she was to sing many times during her career. After the performance, Richard Strauss himself said: "That girl will be the Arabella someday!"