Original sentence: Although Mary Burrell died before completing the biography, the Burrell Collection of Wagner's letters, including many from Minna, were eventually published in 1950, and the originals are in the Curtis Institute of Music in Philadelphia
Edited sentence: Although Mary Burrell died before completing the biography, the Burrell Collection of Wagner's letters, including many from Minna, were eventually published in 1950, and the originals were in the Curtis Institute of Music in Philadelphia