The Trinities of Carnatic Music, Saint Thyagaraja, Muthuswamy Dikshithar and Syama Shastri were all born in Thiruvarur near Thanjavur and the songs composed by them have explored & exhibited the depth and the rich feeling in this form.

The subject matter of the songs mainly dealt with the various Gods and Goddesses, extolling their lives, their virtues, reflecting the varied moods of humans like happiness, gratitude, fear, sorrow.  Though Composers have also dealt with subjects like patriotism, natures bounty etc., their soul and heart were to a very great extent limited to the deities they considered prime. Music was also looked upon as a means of attaining Moksha ( Salvation ).  

Sa Re Ga Ma Pha Dha Nee are the seven basic notations called the Sapthaswaras. The swaras Sa & Pa help select the sruthi/pitch of the singer. Re (Rishaba) & Gha (Ghandaram) are of three types each, Ma (Madhyamam) of 2 types, Dha (Dhaivatham) and Nee (Nishadham) of three types each and when grouped together these variations (6,2,6) combined to form the 72 main ragas, the Melakarthas. The Melakarthas are divided as Suddha Madhyama and Prathi Madhyama ragas based on their madhyama(ma) variations by Venkata Mahi as Venkata Mahi Chakra.  

Ragas born from Melakartha Ragas are aptly termed as Janya Ragas. Janya Ragas are classified into three categories viz., Sampoornam - seven swaras, Shadavam - six swaras and Oudavam - 5 swaras. Janya ragas follow the Kartha raga ie., they contain the same swaras of the original raga in various permutations and 483 variations becomes apparent to form 34,766 Janya Ragas.  

The Janya Ragas gets further subdivided as Upanga Raga, Bhasanga Raga and Vakra Raga. Upanga Raga allows for deletions and additions of swaras. Bhasanga Raga has swaras in addition to swaras from its original raga and the Vakra Raga has swaras in a non-sequential order.  

The Ragas either follow an ascending order, " Aarohanam" or a descending order the "Avarohanam" and the composers took great care to adhere to the various rules when composing a song.  

The song composed are set to thala depending on the number of beats. The thalas are divided into Thisra - three, Misra - four, Kanda - five, Sadhusra - seven, Sankeernam - nine and the song composed fits into one of the above. Aadhi, Rupakam and Chapu are some of the Thalas. 
 
The confluence of the Ragas and the Thalas have from early times been providing us with melodious patterns which when rendered with bhava (feeling) is an experience that has to be had to be believed.