This section is from the book "Some Contributions Of South India To Indian Culture", by S. Krishnaswami Aiyangar. Also available from Amazon: Some Contributions of South India to Indian Culture.
Among the Siva Bhaktas a certain number stand out as pre-eminently the devotees of Siva. They attained to this distinction by various kinds of service extending from the simplest to the most exacting. These are grouped into two classes by the Saivas. The first class consists of sixty-three and stand, each one by oneself. Then follow nine who are taken altogether in one group, constituting on the whole seventy-two. These are the recognised Saints of the Saivas. The Saiva canonical literature of prime importance consists of one group called Arutpa as a group. This group consists of the Tevaram of the three most prominent of the devotees: Sambandar, Appar, and Sundara. The next is Tiruvasagam, Tiruvisaippa and Tiruppallandu, all of them the work of Manikkavasagar. This is followed of course, by an outcrop of other literature dependent on these.
The chronology of these Adiyars cannot yet be regarded as a settled matter, but a rough and ready classification of these is possible from internal evidence of their works alone. They might all be regarded as pertaining to the age of the Pallavas, and this group of devotees had all lived and passed away before the Pallava dominance in South India gave place to that of the Chola. Practically the last of them Sundara composed a poem of 11 stanzas in which he describes himself poetically as a servant of all the rest of them who devoted themselves to the service of Siva, and the date of Sundara had been for various reasons allotted to the commencement of theninth century as that of his contemporary Seraman Perumal. Eearly ninth century therefore would be the downward limit of the sixty-three Nayanmars. The upward limit is not as easily, or even with the same degree of confidence, fixable. One at least of the earliest lends himself to this kind of inquiry and that is the early Chola king, Ko-Chengan. Even the Saiva hagiologists have but little of historical detail to give us regarding him. All that they vouchsafe to us is that a spider devoted itself to the service of Siva at Tiruvanaikkaval by weaving its web over the linga every day to prevent leaves dropping on the image. Every morning, at the same time, a white elephant used to come for performing worship. The elephant used to sweep off the cob-web, pour over the linga the water that it had brought in its trunk, and offer a few flowers similarly brought with it. Wearied by this act of wanton destruction of his own efforts, the spider managed to get into the trunk of the elephant and worried him so much that unable any longer to bear the pain the elephant struck its trunk against the earth violently and died; the spider also died in its pious efforts to destroy the elephant which so regularly and wantonly molested him in his act of worship. For this act of devotion the spider was ordained by the grace of Siva to be born a Chola prince. So he was born of the Chola king Subha Deva and his wife Kamalavati. The only feature of this story that might be at all considered historical is, and that is almost practically the only detail given of his life, that he built the temple of Tiruvanaikkaval (Jambukesvaram) across the river Kaveri from Trichinopoly. His special service of devotion to Siva therefore consisted in the construction of temples to Siva either by himself or through the agency of his officials. A later Vaishnava Alvar Tirumangai, the last of them, speaking of the Vishnu temple at Tirunaraiyur goes out of his way to state in clear terms1 that he built seventy temples to Siva. We may therefore take it that he was a historical person who contributed to the development of Saivism by the particular service of constructing numbers of Siva temples, and the mention of such by a Vaishnava Alvar has its own peculiar, significance. Both Appar and Sambandar of whose age we have some precise knowledge, allude in several places to the transformation of the spider into the Chola king.1 This would mean that by their time the miraculous transformation had got so much into vogue that neither they nor their audience had any difficulty in accepting it as true. That would make Ko-Chengan anterior to the age of the great Pallavas of Kanchi whose period of rule began about A.D. 600.
1 Periya-Tirumoli: VI. vi. 8.
There is a Ko-Chengan who fought a battle against a Chera King whom he threw into prison after defeating him in battle. A poet by name Poygaiyar, who seems identifiable with the Vaishnava Alvar Poygai, celebrated the battle of Kalu-malam (generally taken to the Siyali) in the poem of 40 Stanzas known in Tamil literature Kalvali, forty. This identification rests on literary and stylistic grounds alone so far. There are certain historical considerations that make him contemporary with the Tondaman Ilam Tiraiyan of Kanchi.2 This line of investigation therefore would take Ko-Chengan to a period which may be the closing period of the so-called Sangam literature.
1 Appar, Tirunallaru 5; Sambandar, Arisilkaraipputtuer 7; Tiru-. vaikal,4; Ambar, 1. 2, 5 and !).
2 Early History of Vaishnavism, pp. 73. at seg.
Of the three Tevaram hymners, we have referred Sundara to the commencement of the ninth century. The other two were contemporaries according to tradition, and several historical circumstances connected with each of the two, bring them into contemporaneity likewise. Appar lived to be a very old man, was born a Saiva, became a Jain, and at the latter end of his life returned to Saivism and was instrumental in converting the great Pallava king Mahendravar-man. The other, Sambandar, was his younger, but the more distinguished contemporary, who visited another Saiva devotee Siruttondar in the course of his peregrinations at Tiruchengattan-gudi. This Siruttondar was the general of Mahendra's son Narasimha, and rendered valiant service to his master in the destruction of Vatapi (Badami), the capital of the Western Chalukyas under Pulikesin II. This battle was fought some time about A.D. 642, and therefore these two Sambandar and Siruttondar must have lived about that time and a little later. Appar, as the older, was apparently the contemporary of the father and the son among the Pallava rulers, and probably lived to the middle of the seventh century. The Adiyars who are referred to either directly or allusively in the works of these two, Sambandar and Appar, have to be classified as the early Adiyars; Sambandar and Appar and their contemporaries as perhaps the middle ones; Sundara, Seraman Perumal and those that could be associated with them as the last ones. Ko-Chengan was probably one of the earliest of those that flourished from say about A.D. 200 to A.D. 600, that is among the early Adiyars.