The origin of Carnatic Music may be traced to Sama Veda believed to be written at the beginning of the Christian era. This belief is further bolstered when we see more elaborate elucidation of Carnatic Music and ragas in the famous Tamil epic, Silapadikaram by Elangovadigal dating to the 2nd century.
Indian classical music branched off into two distinct styles: Hindustani style popular in the North of India; Carnatic style pupular in the South.
Silapadikaram mentions seven girls standing in a circle and dancing. Each girl is known by a Tamil word to denote the seven musical octaves – kural (SA), tuttam (RI), kaikkalai (GA), uzhai (MA), ili (PA), vilari (DA) and taram (NI).In South Indian music the seven swaras (or octaves) were named shadja, rishabha and so on for the very first time at a place called Kudimiyamalai in South India. The octaves then got divided into twenty-two mantras. These Sanskrit words were first mentioned in Brahaddesi by Matanga when he was trying to explain tonal variations while rendering swara and varna elevating them to form different ragas. Saranga Deva who followed Matanga was another musicologist much venerated throughout India.
In time Carnatic Music came under more elaborate study by Vidyaranya, Govinda Dikshitar, and Venkatamakin. Vidyaranya classified ragas into fifteen parent or mela scales. These mela scales got further elaborated and Venkatamakin’s Chaturdandi Prakashika (circa 1615) classified them into seventy-two ragas. These continue to be the bedrock on which Carnatic Music we know bases itself.
Venkatamakin is rightly credited to have classified Carnatic Music on a scientific basis. For example, parent or mela scales were classified based on swaras. Combinations of varying swaras were tried to arrive at the number of parent ragas or popularly known as seventy-two mela karta ragas.
Again these parent ragas went through a series of permutations and combinations. We know them as derived ragas or janya ragas. Musicologists have counted such derived ragas to a staggering figure of 34,776. Out of the seventy-two mela karta ragas, forty are vivadi melas or ragas with irregular scales, and out of them are formed innumerable complex ragas.
But music is not mathematics. It is meant to please or sooth the singer as also the listener. Therefore, far fewer number of ragas were identified based on their auditory aesthetics and they became popular. They continue to be.