According to the Imperial Gazetteer of India, all of ancient Natore was beel (wetland) with the exception of Lalpur. The Aryan migrations to Lalpur and Baraigram date back to the Gupta period in the 5th century.
As stated by the Imperial Gazetteer of India, Natore's ancient landscape consisted entirely of beel (wetlands), with the exception of Lalpur. The migration of Aryans to Lalpur and Baraigram occurred during the Gupta era in the 5th century.