This ancient temple dedicated to Lord Shiva was built using granite by the Chola kings at Thirukollikadu near Thiruthuraipoondi in Thiruvarur district. This temple does not have a tower like many other temples built in this era.Lord Shani is said to have prayed to Agneeswarar, for being blamed for the woes of humans. Lord Siva appeared before him and praised him for being a just planet and asked him to reside in the temple as Pongu Sani, abundantly showering his blessings on devotees.Lord Agni worhsipped the lord here and hence the presiding deity is known as Agneeswarar and the location came to be known as Agnipuri. Nalan after being rid of his Sani dosham by worshipping Sani Bhagwan at Tirunallar, got back his wife, children, kingdom and wealth after worshipping here. King Harichandra is also said to have bathed here and relieved of his doshaand hence the river where he bathed is named after him.The shrine for Sani Bhagavan is located in the south west corner and holds a plough and abhaya hastham in his right hand and a crow in his upper left hand and Uru hastham in his lower left hand. Offerring Oomatham flowers is said to cure mentally illness. Puja with Vanni leaves showers wealth and offering Kondrai flower gives peace & unity in the family.Navagrahas face one another here, which is unique to this temple. The malefic effects of Sani (seven and a half years) are alleviated by worshipping here.