Complex sentence: Helen Francesca Traubel (June 16,1899July 28,1972) was an American operatic dramatic soprano, best known for her Wagnerian roles, especially those of Brünnhilde and Isolde.
Split into simpler sentences: Helen Francesca Traubel (June 16,1899July 28,1972) was an American opera singer. A dramatic soprano, she was best known for her Wagnerian roles; especially those of Brünnhilde and Isolde.