<P> Similar problems are encountered at lower levels of classification . </P> <P> Ancient Chinese and Indian systems of classification were based on the materials of which the instruments were constructed, and the acoustic properties of the instruments, respectively . </P> <P> In the 14th century Jean de Muris produced a classification system which divided all musical instruments into three classes: Percussion, String and Wind . Hornbostel--Sachs further develops this scheme, but abandons the percussion high - level grouping, replacing it by the groups idiophones and membranophones . </P> <P> Hornbostel--Sachs classifies musical instruments by means of a numerically labelled inverted tree structure, originally with four groups at the highest level, two of which are percussion instruments (as the term percussion is normally understood), and the others strings and wind . The system does use the term percussion but at a much lower level in the tree and in an esoteric sense quite unlike its common usage, see below . </P>

The classification system of instruments based on -phones was created by