Modern classical music is music written in the 20th century and beyond. Although much of it draws heavily on earlier forms, modern composers also experimented with rejection of long-held ideas; notably, Arnold Schoenberg questioned the traditional notions of harmony with his twelve-tone system[?], and John Cage questioned the very definition of music with his use of chance and found sounds.
... rime, a fact first announced by K.
Hirsche in 1874. The four books are not found
in all the manuscripts, nor are they arranged invariably
in the same order.
The ...