And here is what NAdamunigal came to know about the divya prabandhams: When TirumangaiazhvAr went to Srirangam for NammazhvAr's pradishtai with the blessings of SrI RanganAdar on MArgazhi Sukla EkAdasi, for 20 days the TiruVAimozhi was sung with vEda PArAyanams. This was celebrated as a big TiruvatyayanOtsavam every year. As time went by, the Azhvar could not continue this utsavam any more and the prabandams faded away from common knowledge and practice.
On hearing about this, NAdamunigal was determined to bring the prabandams back to their former glory. He went to Srirangam and revived the TiruvatyayanOtsavam with his special twist on the celebrations: 2000 prabandams were sung on the 10 days from pradamai. For 10 days from EkAdasi, the TiruvAimozhi was sung and the remaining 1000 prabandams were sung after that. So the festivities lasted for a period of 12 days, thus.
From there, he undertook a journey to Tirukkudandhai and by the grace of ArAvamudan, he established a shrine for NammAzhvar there. Here too the Tiruvatyayanotsavam was performed. He christened peruMal with the name of ArAvamudaDasan. He had the full graces of the lord for establishing an important aspect of VishitAdvaitam - the divya prabandhams. After these arduous tasks, he returned to VIranArAyanapuram.
Life continued under the blessings of SrI MannAr. He imparted his kowledge of the prabandhams to 2 sishyAs: KIzhaiyagaththAzhvAn and MElaiyagaththAzhvAn. He sent some of his disciples to SrI Rangam to perform anushtAnams for SrI RanganAdar. Just as Vyasa expounded the vEdas, NAdamunigal expounded the prabandams by setting them to exuberant tunes.
Gangai konda ChOzhan was the king at that time and in his royal sabA - he was once visited by 2 courtesans. One of them was a big proponent of DEvaganam (songs about the Lord) while the other was famous for her ManushyagAnam (songs about ordinary JIvatmAs). Both presented their material at the King's court. The King took a liking to the ManushyaGana courtesan and showered her with favors while completely ignoring the DEvagana courtesan. But she brushed it aside and went on a pilgrimage of the divya desams, enthralling everyone with her mellifluous music.
She came before SrI MannAr and captured everyone with her talent. NAdamunigal sensed her bhakti and showered her with prasAdams from the Lord. She went back to the King and suggested that in order to understand the superiority of DEvaganam, he should invite NAdamunigal to his court and have him explain it. On the bequest of his true disciples in the kingdom, NAdamuni decided to oblige to the King's wishes.
He was welcomed with a lot of respect at the King's court. The King humbly asked NAdamuni what was so special about the DEvaganam of the courtesan. NAdamuni offered to explain with an example. He took a pair of his manjIrA (jAlrA as we call it in colloquial Tamil) and put it inside one of the stone pillars at the palace. He then had the courtesan sing her DEvaganam with bhakti. The stone pillar melted and turned into water. At this juncture he asked her to stop singing - he asked the courtiers to try to retrieve the manjIrA from the molten pillar, but no one could. He then asked her to resume signing and proved that only as long as she was singing, was it possible to reach the manjIrA and retrieve it. He then sounded 400 manjirAs at the same time and proved that the musical ability of that specific maanjIrA was far superior to that of the others - this was due to the power of the dEvaganam.
The King was very pleased with this explanation that wanted to shower NAdamuni with lots of wealth and gifts. Being void of material pursuits, NAdamuni refused those gifts and came back home. The courtesan was well taken care of by the King and the King ruled as a devoted disciple of SrIman NAdamunigal from that day on.
NAdamunigal is also responsible for gracing us with great works like NyAyatatvam and YOgarahasyam.
NAthEna muninA thEna BhavEyam NAthavAnaham
Yasya Naigamikam tatvam HasTamalakatAm gatam.