The roots of western classical music lie in early Christian liturgical music, and its influences date even further back to the Ancient Greeks. Development of individual tones and scales was done by ancient Greeks such as Aristoxenus and the mathematician Pythagoras. Pythagoras created a tuning system and helped to codify musical notation. Ancient Greek instruments such as the aulos (a reed instrument) and the lyre (a stringed instrument similar to a small harp) eventually led to the modern day instruments of a classical orchestra. The antecedent to the early period was the era of ancient music from before the fall of the Roman Empire (476 AD). Very little music survives from this time, most of it from Ancient Greece.

The major time divisions of classical music are the early period (which includes Medieval (476 – 1400) and Renaissance (1400 – 1600)), the Common practice period (which includes Baroque (1600 – 1750); the Classical (1730 – 1820) and Romantic (1815 – 1910)) periods, and the modern and contemporary period which includes 20th century classical (1900 – 2000) and contemporary classical (1975 – current).

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 Mozart, who is generally 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 it is other characteristics of their music that 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, romantic, or modern. Stravinsky’s Pulcinella, for example, is a neoclassical composition because it is stylistically similar to works of the Classical period.

The Classical period, from about 1750 – 1820, established many of the norms of composition, presentation and style, and was when the piano became the predominant keyboard instrument. The basic forces required for an orchestra became somewhat standardized (although they would grow as the potential of a wider array of instruments was developed in the following centuries). Chamber music grew to include ensembles with as many as 8-10 performers for serenades. Opera continued to develop, with regional styles in Italy, France, and German-speaking lands predominating. The opera buffa, or comic opera, gained in popularity. The symphony came into its own as a musical form, and the concerto was developed as a vehicle for displays of virtuoso playing skill. Orchestras no longer required a harpsichord (which had been part of the traditional continuo in the Baroque style), and were often led by the lead violinist (whom we now call the concertmaster). More instruments too became integrated along with the music.

A culture’s music is influenced by all other aspects of that culture, including social and economic organization and experience, climate, and access to technology. The emotions and ideas that music expresses, the situations in which music is played and listened to, and the attitudes toward music players and composers all vary between regions and periods.  The Classical “Music history” is the distinct subfield of musicology and history which studies music (particularly western art music) from a chronological perspective.

If “classical” can be taken to mean what it often in fact means, “serious”, then the earliest American classical music consists of part-songs used in religious services during Colonial times. The first music of this type in America were the psalm books, such as the Ainsworth Psalter, brought over from Europe by the settlers of the Massachusetts Bay Colony. The first music publication in English-speaking North America — indeed the first publication of any kind — was the Bay Psalm Book of 1640.

Many American composers of this period worked (like Benjamin West and the young Samuel Morse in painting) exclusively with European models, while others, such as William Billings, Supply Belcher, Daniel Read, Oliver Holden, and Justin Morgan, also known as the First New England School, developed a native style almost entirely independently of European models. Many of these composers were amateurs, and many were singers: they developed new forms of sacred music, such as the fuguing tune, suitable for performance by amateurs, and often using harmonic methods which would have been considered bizarre by contemporary European standards. Some of the most unusual innovators were composers such as Anthony Philip Heinrich, who received some formal instrumental training but were entirely self-taught in composition. Heinrich traveled extensively throughout the interior of the young United States in the early 19th century, recording his experiences with colorful orchestral and chamber music which had almost nothing in common with the music being composed in Europe. Heinrich was the first American composer to write for symphony orchestra, as well as the first to conduct a Beethoven symphony in the United States (in Lexington, Kentucky in 1817).

In the early 20th century, George Gershwin was greatly influenced by African American classical music however, this was during an era of legally enforced Jim Crow racial segregation during which his music perhaps enjoyed undue fame owing to the refusal of white listeners to listen to music that formed Gershwin’s sources.On the other hand, he created a convincing synthesis of music from several traditions once considered to be irreconcilable, and which continues to enjoy enormous popularity.In the 1980s, after a period during which self-defined American “classical” composers like John Cage adopted atonal structures and thought of themselves less American than Modern composers, Philip Glass revived tonality and traditional genres, such as opera in works like Einstein on the Beach. Glass re-created a semi-mass market for “classical” music, made in America because audiences outside of an avant-garde had simply refused to sit still for Modernist, atonal music, whether from America or Europe.

There are, likewise, numerous examples of influence flowing in the opposite direction, including popular songs based on classical music, the use to which Pachelbel’s Canon has been put since the 1970s, and the musical crossover phenomenon, where classical musicians have achieved success in the popular music arena (one notable example is the Hooked on Classics series of recordings made by the Royal Philharmonic Orchestra in the early 1980s). Some rock bands such as Emerson, Lake & Palmer have recorded classical compositions.

Composers of classical music have often made use of folk music (music created by musicians who are commonly not classically trained, often from a purely oral tradition). Some composers, like Dvoák and Smetana, have used folk themes to impart a nationalist flavor to their work, while others (like Bartók) have used specific themes, lifted whole from their folk-music origins.
Certain staples of classical music are often used commercially (that is, either in advertising or in the soundtracks of movies made for entertainment). In television commercials, several loud, bombastically rhythmic orchestral passages have become cliches, particularly the opening of Richard Strauss’ . Also sprach Zarathustra (made famous in 2001: A Space Odyssey) and the opening section “O Fortuna” of Carl Orff’s Carmina Burana; other examples in the same vein are the Dies Irae from the Verdi Requiem, Edvard Grieg’s In the Hall of the Mountain King from Peer Gynt, the opening bars of Beethoven’s Symphony No. 5, Wagner’s Ride of the Valkyries from Die Walküre, Rimsky-Korsakov’s Flight of the Bumblebee, and excerpts of Aaron Copland’s Rodeo.

During the 1990s, several research papers and popular books emergence touting the so-called Mozart effect: a temporary, small elevation of scores on certain tests as a result of listening to Mozart.One of the co-authors of the original studies of the Mozart effect commented “I don’t think it can hurt. I’m all for exposing children to wonderful cultural experiences. But I do think the money could be better spent on music education programs.”

Throughout history, parents have often made sure that their children receive classical music training from a young age. Some parents pursue music lessons for their children for social reasons or in an effort to instill a useful sense of self-discipline. Some consider that a degree of knowledge of important works of classical music is part of a good general education.

The Samaveda, one of the four Vedas, describes music at length. The Samaveda was created out of Rigveda so that its hymns could be sung as Samagana; this style evolved into jatis and eventually into ragas. Indian classical music has its origins as a meditation tool for attaining self realization. All different forms of these melodies (ragas) are believed to affect various “chakras” (energy centers, or “moods”) in the path of the Kundalini. However, there is little mention of these esoteric beliefs in Bharat’s Natyashastra, the first treatise laying down the fundamental principles of drama, dance and music.

Indian classical music has the most complex and complete musical systems ever developed. Like Western classical music, it divides the octave into 12 semitones of which the 7 basic notes are Sa Re Ga Ma Pa Dha Ni Sa, in order, replacing Do Re Mi Fa So La Ti Do. However, it uses the just intonation tuning (unlike most modern Western classical music which uses the equal temperament tuning system).

Indian classical music is monophonic in nature and based around a single melody line which is played over a fixed drone. The performance is based melodically on particular ragas and rhythmically on talas.

The Main genres of Indian Classical Music are Hindustani classical music ( originally from North India) & Carnatic music (Originally from South India)

In Hindustani music, the performance usually begins with a slow elaboration of the raga, known as alap. This can range from long (30-40 minutes) to very short (2-3 minutes) depending on the style and preference of the musician. Once the raga is established, the ornamentation around the mode begins to become rhythmical, gradually speeding up. This section is called the drut or jor. Finally, the percussionist joins in and the tala is introduced. Instruments typically used in Hindustani music include the sitar, sarod, tanpura, bansuri, shehnai, sarangi and tabla.The prime themes of Hindustani music are romantic love, nature, and devotionals.

Carnatic music tends to be significantly more structured than Hindustani music; examples of this are the logical classification of ragas into melakarthas, and the use of fixed compositions similar to Western classical music. Carnatic raga elaborations are generally much faster in tempo and shorter than their equivalents in Hindustani music. The opening piece is called a varnam, and is a warm-up for the musicians. A devotion and a request for a blessing follows, then a series of interchanges between ragams (unmetered melody) and thaalams (the ornamentation, equivalent to the jor). This is intermixed with hymns called krithis. This is followed by the pallavi or theme from the raga.Instruments typically used in Carnatic music include venu, gottuvadyam, veena, mridangam, kanjira, ghatam and violin.

Indian classical music has given wonderful musicians to the world. Notable vocalists include Kesarbai Kerkar, Roshanara Begum, Subbulakshmi, G. N. Balasubramaniam, Balamuralikrishna, Ariyakudi Ramanuja Iyengar, Vishnu Digambar Paluskar, D. V. Paluskar, Abdul Karim Khan, Abdul Waheed Khan, Faiyaz Khan, Amir Khan, Bade Ghulam Ali Khan, Kumar Gandharva, Omkarnath Thakur, Narayanrao Vyas, Mallikarjun Mansur, Nazakat and Salamat Ali Khan, pandit Bhimsen Joshi, Mogubai Kurdikar, Kishori Amonkar, Ulhas Kashalkar and Rashid Khan.