The Vanmikanathar Legend

Legend has it that Vishnu came to possess a great bow that rendered him with great might. Seized with vanity, Vishnu is said to have chased the Gods or the Devas all through the Universe. The frightened Devas fled all over the Universe and finally came to Tiruvarur and offered prayers to Shiva requesting him to save them from this plight.

It is said that Vishnu's strength vanished upon his reaching Tiruvarur and he is said to have stood still, resting his head on his bow. The Devas immediately took the form of white ants, built an ant hill at the end of the bow that rested on the ground, gnawed at the bow and cut off its string. The straigtening bow struck Vishnu with much force and cut off his head.

Totally dismayed at the loss of the protector of the Universe, the Devas prayed again to Shiva. Shiva appeared immediately and restored Vishnu to life, and upon the request of the Devas took up abode within the anthill, and is now enshrined within the anthill, as Vanmikanathar in the main shrine of the Tiruvarur temple complex.

It is believed that there was an earlier shrine to Shiva at Aatakeswaram, near the stala vriksham (temple tree). There is only a subterranean passage there now and it is believed that Shiva - Aatakeswara appeared as Vanmikanathar or Putridamkondaar (the one who appeared within an anthill) to restore to life, the protector of the Universe.

It is to be noted that the Vanmikanathar (moolavar)shrine at Tiruvarur is older than the better known shrine dedicated to Tyagaraja.

Also see:
All about Shiva
Shivalinga Worship