Anbil was in existance before the Pandavas. Perumal is said to have appeared here in response to prayers of Brahma and Sri Valmiki. There is an interesting episode involving the pushkarani at this sthalam. The Manduka pushkarani is common to both Vishnu and Siva sthalam. Mandukam, in Sanskrit refers to a frog. It is said that, once upon a time, a muni was cursed and he became a frog. He wanted to regain his human form. So he had bath every day in the tank, for 48 days he observed a vratha and prayed to Perumal regularly. Lord appeared before him and redeemed him from the curse. The pushkarani has therefore been named after the rishi who became a Mandukam.








Source:
1. 108 Vasihnavaite Divya Desam by Miss M. S. Ramesh.