Lord Vishnu emerged as a Kadambha tree at this place, giving the name "Kathambanur", which later became "Karambanur". The name Karambanur is mentioned by Thirumangai Azhwar in Nalayira Divya Prabandam, in which he refers the presiding deity as "Karambanur Uthaman". The temple is commonly called "Uthamar Kovil" after the name of the presiding deity. The temple is also called Bhikshandar Kovil as the Hindu god Shiva is present in the form of Bhishadanar (a mendicant) and believed to have attained cure by worshiping Vishnu at this place. As per history, once Lord Vishnu wanted to test the devotion of Brahma. He raised as a Kadhamba tree in the place and Brahma, knowing this, started his worship practise with Thirumanjanam (ablution). The water from the ablution filled a tank nearby, which came to be known as "Kathamba Theertham". Vishnu was satisfied with the devotion of Brahma and gave a boon to Brahma to have a shrine in this place. Shiva wanted to get rid off the sin holding the cut head of Brahma and went on a sacred trip. While coming to this place, Vishnu requested his consort Lakshmi to give alms to Shiva. Shiva's grail was filled by the alms and Lakshmi came to be known as "Poornavalli" (the one who filled the grail).