The Swiss soprano Lisa Della Casa was a major presence on the international opera scene from the late 1940's to the mid 1970's, particularly at the Vienna State Opera, Covent Garden in London and the for 15 seasons at the Metropolitan in New York. Mozart and Strauss dominated her repertoire, but not always by choice. She asked Rudolf Bing to sing more Italian and French roles, but he insisted that he had a surplus of sopranos for those roles, and that she was indispensible for Mozart and Strauss. And when she sings Mozart and Strauss, we understand his thinking, if not his stubbornness. She sings Mozart , Strauss and others including Puccini this Sunday night at 8PM.