Classical music is the art music produced in, or rooted in, the traditions of Western liturgical and secular music, encompassing a broad period from roughly the 11th century to present times. The central norms of this tradition became codified between 1550 and 1900, which is known as the common practice period. European music is largely distinguished from many other non-European and popular musical forms by its system of staff notation, in use since about the 16th century. Western staff notation is used by composers to prescribe to the performer the pitch, speed, meter, individual rhythms and exact execution of a piece of music. This leaves less room for practices such as improvisation and ad libitum ornamentation, that are frequently heard in non-European art music (compare Indian classical music or the Hindustani classical music of South Asia and Japanese traditional music) and popular music.

Given the extremely broad variety of forms, styles, genres, and historical periods generally perceived as being described by the term "classical music," it is difficult to list characteristics that can be attributed to all works of that type. Vague descriptions are plentiful, such as describing classical music as anything that "lasts a long time," a statement made rather moot when one considers contemporary composers who are described as classical; or music that has certain instruments like violins, which are also found in other genres. However, there are characteristics that classical music contains that few or no other genres of music contain.

The major time divisions of classical music are the early music period, which includes Medieval (500вАУ1400) and Renaissance (1400вАУ1600), the Common practice period, which includes the Baroque (1600вАУ1760), Classical (1750вАУ1830) and Romantic (1815вАУ1910) periods, and the modern and contemporary period, which includes 20th century (1900вАУ2000) and contemporary (1975вАУcurrent). The dates are generalizations, since the periods overlapped and the categories are somewhat arbitrary. For example, the use of counterpoint and fugue, which is considered characteristic of the Baroque era, was continued by Haydn, who is classified as typical of the Classical period. Beethoven, who is often described as a founder of the Romantic period, and Brahms, who is classified as Romantic, also used counterpoint and fugue, but other characteristics of their music define their period. The prefix neo is used to describe a 20th century or contemporary composition written in the style of an earlier period, such as Classical or Romantic. Stravinsky's Pulcinella, for example, is a neoclassical composition because it is stylistically similar to works of the Classical period...