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.
In the Imperial Gazetteer of India, it is noted that all of Natore was marshland (wetland) apart from Lalpur. The Aryan settlements in Lalpur and Baraigram began during the Gupta period in the 5th century.