Origin explored
Saiva origin
In the Saiva philosophy it is said that the universe was created by the grace of Sivaperuman (Lord Siva) who performed the cosmic dance of Thandavam to reveal the entire cosmos.
Lord Siva revealed himself as the cosmic dancer Koothan or Nadarajah to materialise the cosmos.
In his right hand Lord Nadarajah holds the Udukkai instrument which beats furiously to accompany the dance of the lord.
According to this philosophy Udukkai thus became the first instrument of the world and indeed the universe.
The lord’s dance getting ever furious was becoming a source of destruction and was at risk of destroying the entire universe. Realising this, the lord understood that he must slow the tempo of the dance in order to save the universe.
To stop the fast beat Lord Nadarajah immediately threw the Udukkai which burst into two parts producing an indescribably loud bang noise. This was the sound of creation and is the source of the piranava manthiram, the AUM.
The two pieces of the broken Udukkai was joined in a reverse order by the lord thus producing the Mathalam. The lord taught the art of the Mathalam to his carrier Nanthikeshwar (Lord Nanthi, the Bull headed demigod). Lord Nanthi thus became the master percussionist and continued to accompany the Thandavam dance of Lord Siva.
The Mathalam is the ancestor of the Miruthangam and resembles the Miruthangam not only in its shape but also the tonic pitch variability.
Natural origin
Tamil music, like every other aspect of Tamil culture, reflects centuries of influences and changes produced during its 3,000 years of recorded history with the immigration of the Aryans from Central Asia in the second millennium B.C.
With each group came new cultural ideas and technical innovations, and with the passage of time, the new ideas were absorbed and assimilated, emerging finally in an undeniably Tamil synthesis.
This is how the Pann isai, an ancient Tamil musical system, changed over time to form the Carnatic musical system. Along with the changes in the musical systems the Mathalam also underwent dramatic modifications to produce the Miruthangam, an instrument that is now perfect for Carnatic music.
However, both Pann isai and Mathalam did not die out they are still very much in use today. Saiva hymns (Thevaram, Thiruvasagam etc) are still sung in the intricate Pann isai system (Pann is equivalent to Ragam) and the Mathalam continues to accompany traditional Koothu dance and drama that are still performed by Tamils worldwide.
Just like the evolution of the Mathalam to Miruthangam, most of the Tamil musical instruments have evolved over centuries the same way. Each instrument has its own history behind its evolution. In Tamil culture's early stages, artefacts, musical instruments, and lifestyles were simple and basic in nature.
All tribal instruments, for example, are basic rhythm instruments and never complex instruments having a capacity to produce a range of octaves.
As a society progressed, the demands on musical instruments arose. Thus, most Tamil instruments, although having started in simple forms, because of a long period of evolution, have now become exquisite instruments capable of producing a varied pitch and range of octaves.