 Both Hugo Riemann and Heinrich Schenker implicitly or explicitly refer to the theory of the chord of nature (which they recognize as a triad, a "Dreiklang"), but both reject the theory as a foundation of music because it fails to explain the minor triad.The theory of the chord of nature goes back to the discovery and the description of the harmonic partials (harmonic overtones) in the 17th century.The word "klang" (or "clang") has often been used in English as a translation of the German "Klang" ("sound"), e.g.