What German composer wrote a letter in 1770 addressing Lucrezia Aguiari's ability to perform in C sporano acuto?
Lucrezia Aguiari:  In a letter dated 24 March 1770 Leopold Mozart wrote of hearing her perform a C an octave above high C at the Ducal opera of Parma, "I could not believe that she was able to reach C soprano acuto, but my ears convinced me."
i don't know