Believed  to have been built 500 years ago, the temple is dedicated to Lord Shiva. As the legend goes, a priest once had a cow which refused to be milked. Upon following the cow, the priest found that the cow gave milk on a bush of “virina” (type of grass). When the king came to know about it he got the place dug and found a Shiva Linga on that spot. A temple was built which was first called Birreswar or God or Virina, then Billeswar and now Belsor. Nowadays Belsor is a developed village  with easy accessibility. Throughout the ages this temple has attracted many devotees and received royal patronage, including the Ahom King, Lakshmi Singha, who rebuilt the temple after it was devastaed by natural calamity. It is situated about ten k.m. south-west from Nalbari Town.