Generally temples have idols made of dark granite but the idol of Guruvayurappan is made out of a rare pataalanjana sila and hence extremely divine. This image of Lord Krishna was once worshipped by the supreme God Vishnu himself in vaikundha. He handed it over to Brahma gave it to suthapas and he, in turn gave it to kasyapaprajapathy. Kasyapa handed it over to Vasudeva, the father of Sree Krishna and from Vasudeva it reached Sree Krishna himself Sree Krishna kept it in Dwaraka and worshiped it, and at the time of his ascension to heaven, he directed Uddhava to tell Brihaspathy – the preceptor of Gods –to take the idol, which would be seen above the waters when Dwaraka got submerged and install it in a proper place for all the people to worship and get salvation in kaliyuga.

Brihaspathy, helped by Vayu went throughout the world, in search of the most holy and; suitable place. Then at the invitation of Parasurama, they came to kerala and reached Rudratheetha where Siva was doing tapas. Divining the purpose of Guru and Vayu, Siva came up from the water, received them and told them “this is the most holy place you are searching for”. I have been doing penance here for the last so many yugas. It was here that prachethas did tapas and it was here that I gave the upadesa of Rudrageetha. This place had been marked out long ago for the divine idol of Narayana worshipped by Narayana himself. I shall most gladly leave this place and reside with Parvathy on the opposite bank at Mammiyur.

Guruvayur is made divine by the prolonged Tapas by both Siva and prachethas in the Rudratheertha which is now Arattukulam of Lord Guruvayurappan. Under the waters of the Rudratheertha Siva was worshipping Maha Vishnu. To this place came Prachetas, as directed by his father Pracheenabarhis. Foreseeing the object of Pracheethas Siva came up from the water and imparted to him the Rudrageetha in praise of Mahavishnu and disappeared in to water, to resume his Tapas. Prachetas standing in the Rudratheertha started worshipping Mahavishnu. At the end of ten thousand years Mahavishnu appeared before him and granted his wish for a virtuous son. The child born was Dakshaprajapathy.