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.
... however, François reneged on the treaty. The 1529 Treaty of Cambrai[?] (signed with France) and the Peace of Barcelona[?] (with the Pope) confirmed Charles as Holy ...