Sanctity of the  Place 

Guruvayur became divine on account of the "tapas" performed by Lord Siva and later by the Prechethas (the ten sons of Pracheenabarhis and Suvarna are together called Prechethas) in the Rudratheertham - the sacred tank on the northern side of the present temple - where Lord Guruvayurappan has His Arattu (holy bath on the last day of Annual Utsavam). Siva worshipped Mahavishnu for years under the waters of the Rudratheertham ( hence the name Rudratheertham due to the presence of Rudra, Siva). Prechethas came to this place to do tapas to attain "prajapathithwam" ( king of all kings) from Lord Mahavishnu. Sensing the motive of Prechethas, Lord Siva emerged out of the Rudratheertham and revealed to them the "Rudrageetham", a hymn in praise of Mahavishnu. Siva suggested them to chant it with all their heart to get their wishes fulfilled. The Princes won the favour of Mahavishnu after rigorous tapas for 10,000 years under the waters of Rudratheertham chanting Rudrageetham.

According to the legends, in ancient days Rudratheertham ( present Arattukulam) extended up to Mammiyur and Thamarayur (about 3.00 kms) towards north and was known for its lotus flowers. Melpathur's Narayaneeyam refers to it as the lovely lake of lotus.