Little did a group of residents who stumbled on a stone idol while walking on the dry Palar riverbed at Puliyankannu village on Saturday know that they had unearthed a 500-year-old treasure - a Lord Vishnu idol.

Residents said that they were returning home from Walajah town to the village when one of the persons stumbled upon the idol, which was buried. They removed a portion of sand around the idol and found a damaged sculpture. “We are surprised to notice the idol as the dry river was our routine route to reach nearby villages and towns,” said R. Mari, a resident.

Residents alerted the village headman, who in turn, informed the police and village administrative officer (VAO). After pain-staking efforts by removing sand from all four sides of the treasure for nearly an hour, workers lifted the stone idol with a mechanised crane in the presence of revenue officials and the police.

Revenue officials said that the head of the Vishnu idol, which is two-feet tall and 1.5-feet wide, was slightly damaged. Two arms, including the one that holds the chakra on the right side of the idol, was intact. Local historians said that the Vishnu idol could be around 500 years old and belong to the Vijayanagara era because it was during this period that the region witnessed more temple-related constructions.

Like Sriperumbudur (the birthplace of saint Ramanuja), the region along Palar River was also a great centre for both Vaishnavites and Shaivites. The Vijayanagara rulers were mostly Vaishnavites, they said.

Revenue officials said that under the Indian Treasure Trove Act 1878, anything found below one feet depth belongs to the government. As per norms, such treasure should be handed over to the district treasury with the Collector being the sole guardian of the treasure. At present, the idol has been kept at the Taluk Office in Walajah town.

Officials of Arcot Site Museum said that a request was to be made to Collector Priya Ravichandran for public display of the granite idol at Arcot Museum as such a measure will help students and other public learn the rich past of the region.

Earlier, such an idol was unearthed from Mellur village near Katpadi in 2008. The five-feet Vishnu idol made of sandstone was the tallest statue, dating to the early Chola period of 9th century at the museum.