During the Pralayam the Puranakumbam (Amirtham in a pot – Bowl of nectar) moved from Maha meru to south direction and reached Kumbakonam. During the great deluge, it is believed that Shiva caused the Amritakalasam to stall here.
Shiva in the form of Kirathamurthy means hunter aimed the Puranakumbam with the bow and arrow called Banam. Siva as Kradha moorthy broke the pot of nectar by his arrow in this place, hence the name banadurai.
The bowl split and the Amirtham got stagnated in two places. One of it Portramaraikulam and the other is Mahamaham tank. A Shiva Lingam formed at the place where Kirathamurthy aimed the Amirthakudam. Since the lord used the Arrow or Banam the deity lingam is called Banapureeswarar. This shrine is said to have been established built and consecrated by Bhrama.