This is the first among the 108 divya dEsams or sacred temples dedicated to Lord Vishnu. The shrines here are Sri RanganAtha, Ranga nAchiyAr or AranganAyaki thaayaar and Andal nAchiyAr. The history of srirangam was given by me in my earlier blog dedicated to Uchi pillayar temple
Out of the 12 AzhwArs (poigaiAzhwAr, boodhathAzhwAr, pEyAzhwAr, periyAzhwAr, tondaradipodiAzhwar, nammAzhwAr, AndAL, kulasEkarAzhwAr, thirumangaiAzhwAr, madhurakavi AzhwAr, thiruppanAzhwAr, thirumazhisaiAzhwAr), 11 (except madhurakavi AzhwAr) have sung pAsurams on this temple. Saint TyAgaraja has sung the sriranga pacharatna (collection of 5 songs) and Muthuswamy dikshithar has song another 5 songs on various deities over here.
This ksetrA is described as bhoolokha vaikundam. Saint tyagaraja has mentioned this in his kamboji raga composition O ranga Sayee. In his todi composition raju vedala juda murare, he has mentioned about the purity and divinity of the river kAvEri.
Dikshithar has mentioned the structure of the vimanam in the song RanganAyakam in the rAga nAyaki as "pranavAkAra divya vimAnam". He has also sung on the mEla pattAbhirama present in the west side of the temple in his brindAvana sArangA song - sri rangapura vihArA.
Tanjore Ponnaiyah pillai has also composed a song - RanganathudE in the rAga sourashtram.
There are 7 prakArAs in the temple. The name of the seven prakArAs are given below:
2. Trivikrama chozhan suttru
3. Kili chozhan suttru
4. Thirumangai aazhwar suttru
5. Kulasekara aazhwar suttru
6. Rajamahendra chozhan suttru
7. Dharmavarma chozhan suttru
But these have another name also. The other names in the same order as above -
The vimanam of the temple is called - pranavaakaara vimanam. (It will be in the shape of Omkaaram)
Aren't these 7 names identical to one of the mantra - Om bhoohu, Om buvaha, oohum suvaha, om mahaha, om janaha, om thapaha and oohum sathyam that will come during sandya vandanam?
So the 7 prakaaraas are the form of these 7 mantras with Omkaaram (main vimanam) at the centre.