The sthalapurana of this Divya Desa is told in Brammanda Purana. Once upon a time, there was a Pralayam in Brahmmaloka and the Lord Brahma was asleep then. Somukhan, an asura, stole the vedas from Lord Brahma. To recover it, the Lord Brahma wanted to do penance to Perumal. He chose this place and did penance. Perumal came down from Vaikunda, killed Somukhan and returned the vedas to Lord Brahma. Lord Brahma requested Perumal to stay here forever and bless his devotees. As this place, on the banks of river Tambraparani, was similar to Vaikunda and as Vaikundanatha himself gave this Darshan here, this was named as Sri Vaikuntham by Lord Brahma.
As in Nava Thirupathi Mahatyam and as repeated by sage Narada to Lord Indra, there is another story of how Perumal was named Kallapiran (Chorantha). A thief, Kaladhooshkan, who lived here, was a devotee of God Vaikundanatha. Every day, before starting his job of stealing, he visited this temple, offered prayers and sought God’s protection. Once, when he stole in the palace, he was chased by the King’s guards, the thief escaped, went to the temple and sought Perumal’s protection. God Vaikundanatha assumed the form of Kaladhooshakan and was taken to the King. During interrogation the King realised that this thief is no ordinary being. Perumal told the King to Donate more of his idle wealth as per Dharma. As God appeared as a leader of thieves and revealed his true form, he came to be known as Kallapiran.