Bangladesh were a proto-Australoid people including the Veddas.
Evidence also suggests that there was a strong Mongoloid presence as well.
Soon after came the Aryans from Central Asia as part of their farthest sweep into deltaic India and the Dravidians from Western India. Later on the Muslims from Arabian, Turkish, Afghan, Persian and other minor stocks became the most important contributors to the vast melting pot of nations which now form Bangladesh. But subsequently they became the rulers of this land holding sway from the 13th to the 18th century. Sometimes they were independent rulers like the Hussain Shahi and Ilyas Shahi dynasties while at other times they ruled on behalf of the Imperial seat at Delhi. After his defeat at Plassey in 1757 the sovereignty of the people of this land passed into the hands of the British.