The term "classical music" can be used in two ways. When it's capitalized, it's usually referring to a historical period (c. 1730-1820), the time of Mozart and Haydn. The other meaning of "classical music" is much broader, covering the entire canon of Western art music, from Gregorian chant to Philip Glass and beyond. It encompasses a vast range of styles, forms and techniques, but in one respect, classical music differs from other types by its use of music notation, which is used by composers to indicate the pitch, speed, meter, rhythms and overall execution of the music. From the simplest song to massive compositions of mind-bending complexity, classical music often attempts to affect the mind, body and spirit in profound ways; the greatest examples succeed in doing just that.