Gradually the classical musical tradition diverged into Hindustani and Carnatic. While there are minor regional variations, Indian classical music was overall an integrated system until around the 13th-14th centuries A.D., when political upheavals led to isolation between the north and south. Yet listeners who know the style will recognize them as the same song. However, Indian classical music includes a great deal of improvisation, so if you hear two different performances of a specific piece, they may be of very different lengths, have more or less ornamentation, and be played in very different instrumental combinations, with or without singers. There are also basic forms such as the raga (Hindustani) and kriti (both styles, but especially Carnatic) which are long-established. The origins of Indian classical music go far into times B.C., and basic concepts of scale and interval have remained essentially constant in Indian classical music for over 2,000 years. Understand Ravi Shankar playing the sitar at Woodstock Festival in 1969 Indian classical music refers to two distinct yet related musical traditions in South Asia: Hindustani classical music in the north and Carnatic classical music in the south.
