The Austrian Theorist and Composer Josef Matthias Hauer evolved a system of 12-tone music which he felt would save music from what he saw as the excesses of the late 19th and early 20th centuries. During the years 1918–26 he formulated his ideas concerning 12-tone music into three short treatises: Vom Wesen des Musikalen: Grundlagen der Zwölftonmusik; Vom Melos zur Pauke: Eine Einführung in die Zwölftonmusik; and Zwölftonmusik: Die Lehre von den Tropen. In these three works Hauer presented his ideas concerning the interval as the point of departure for melody, rhythm, and timbre, as well as his concept of music as a ‘pure’ art, which the composer should only approach through a system of ‘tropes’ or ‘tone-constellations’—theories markedly different from those of his contemporary Arnold Schoenberg.