Equipped with melody and rhythm, music has undergone a magnificent evolution in India. In its sweep it has united earth and sky. Originating in religious worship, it has become a spiritual discipline. Singing by itself thus becomes a spiritual exploration, in addition to being an aesthetic one. The harmony of pure being and dynamic becoming, of the transcendent and the immanent, of eternity and time, is a fundamental doctrine in the Indian tradition.
Indian music has no absolute pitch.
For each occasion of singing, a drone furnishes a frame, a sustained tonal centre. The tonic, heard continuously before, throughout and at the conclusion of the singing, expresses the timeless, eternal background of things . The singing itself is an interlude which builds up tonal space through melodic elaboration spanning the lower and upper tetrachords and tonal time through the organisation of time. Amir Khusrau, the Persian aristocrat and humanist of the 13th century who made India his home, was a great pioneer in this respect. The cultural interaction gained momentum with the establishment of the Mughal empire and, like the architecture and painting of the north, music too got enriched by Persian traditions.