Vallakottai Subramaniaswamy Temple – Legends
Murugan slayed Demon Vallan here:
As per Hindu legend, there was a demon by name Vallan who was troubling the Devas, the celestial deities. The Devas sought the help of Murugan. He informed them that the time had come to destroy the demon. He eventually waged a war and slayed the demon at the place. He established the place as Vallan Kottai, literally meaning the "Fort of Vallan".
Indra worshipped Murugan here:
Indra, the king of Devas, requested his Guru Brihaspati to suggest a place for him to worship Murugan. He suggested going to Vallakottai, an abode of Murugan. Indra came to Vallakottai, pierced the earth with his weapon Vajrayudha to create a tank to extract water. He performed ablution to image of Murugan at this place and attained his needs. Since Indra created the tank with his Vajrayudha, the temple tank is named as Vajra Theertha.
Bhagiratha disrespect to Sage Naradha:
As per another legend, a king by name Bhagiratha was ruling the Elanji kingdom. He was very haughty to sage Naradha and to teach him a lesson for his behaviour, Naradha infuriated a demon king named Goran to attack Elanji kingdom. Goran was a powerful demon and he made a sudden attack. Bhagiratha was unable to control the forces and eventually lost the battle to Goran. Realizing his mistake, he sought the advice of Naradha.
The sage advised him to find sage Durvasa, who could find a resolution. The king roamed around the forest for a long time and finally found Durvasa. The sage advised him to worship Murugan at Vallakottai to get back his kingdom. The king worshipped Murugan at this place for a long time and built the temple.
Lord Murugan appeared to Arunagirinathar in dream to tell about this place:
Arunagirinathar was advised by Lord to Visit this temple on the way to Thiruthani from Thiruporur, in his dream. He has sung 7 hymns in Thirupugazh in praise of Lord Sri Subramaniyar.
Arunagirinathar denotes this Vallakottai as Kotainakar, Kotappati, Kotaiyampati, Kottai enumpati, and Kottai'. Though Arunagirinathar mentioned this place by many names, it is presently popular only as Vallakottai. There are many interpretations available for this name; yet only one seems to be plausible. In Kanchipuram District, near Vallakottai, there is another Murugan, ‘Tirupati' (holy place) by name ‘Vallam'. By connecting this holy place ‘Vallam', the people of the area would have called ‘Vallakottai' first. Afterwards it seems that this holy place would have naturally got the name of Vallakottai.