Aathi Kumbeswara swamy is the main deity of the temple. Aathi is primodal origin implies ancitent or the first and the foremost. The Kumbeswarar is in Shiva Linga form which is a formless form - called aaru (formless) + uru (form)=aaruuru. The shape of the linga is of very special significance it is of conical shaped lingam,This is a unique linga in the world. The Pururanas derives the meaning of the shape and the name. The city name Kumbakonam itself is derived from the name of God - Kumba and the slight angle of the Linga and hence the name"Kumbakonam".
It is one of the 127 temples on the southern banks of the river Cauvery. It is mentioned as,'Thirukkudamooku'in'Thevaram',at present it is called Kumbakonam. It is a prime temple amidst many temples in kumbakonam. The presiding Murti(deity) is'Adhikumbheswara'and His consort is'Mangalambhika'. It is also one of the 64 saktibheta sthala(Mantrabheta sthala). The Siva Linga is slightly tilted at the top towards left and hence the name kumbakonam (kumba - pot;konam -bend) and the deity kumbeshwara.
During cosmic dissolution,a pot containing nectar (Amrta) was floating and lord Siva came in the disguise of a hunter and pierced the pot with an arrow,thereby making the nectar to flow through it's nostril on all sides . Hence this place is named Kudamooku (kuda - pot; mooku - nostril or tip). The objects such as mango leaf,sacred grass (Tharppai),hoop (uri), Bell tree leaf (Bilva), coconut and the sacred thread (poonool)which adorning the pot fell into different places due to whirl wind. They appeared as Siva lingas and later on they became Siva temples. As per puranas the genesis of life happened by the the Thiru Vilaiaadal (divne play) of God Shiva here, and from here all the living beings orginated.
Aathi (Origin) Kumbeswara swamy is the main deity of the temple Aathi Kumbeswarar. The Kumbeswarar (Linga) is on the form of conical lingam. The left of the main deity has another shrine for the goddess namely Mangalambigai. This temple outer prahara has an important shrine called as Kumba muni Siddhar.