Bangladesh has historically been a land of many races. Long before the arrival of the Aryans in the 5th and 6th centuries BC, the Bengalees were already racially mixed and on that count the Aryans described them as sankaras or hybrid people. The ancestors of present-day inhabitants of Bangladesh have therefore emerged from the fusion of each diverse races as the Austric, Dravidian, Mongoloid, Homo-Alpine, Mediterranean Brown, Aryans and so on.
The earliest historical reference to organised political life in the Bangladesh region is traceable to the writings on Alexander’s invasion of India in 326 BC. Greek and Latin historians suggest that Alexander the Great withdrew from India anticipating a valiant counter-attack from the Gangaridai and Prasioi empires which were located in the Bengal region. Historians maintain that these empires were succeeded by the Maura' (4th to 2nd century BC), the Guptas (4th-5th century AD), the empire of Sasanka (7th century AD), the Pala empire (750-1162 AD) and the Senas (1162-1223 AD).
From the 13th century AD, the Buddhist and Hindu rulers were swamped by the flood of Muslim conquerors and the tide of Islam continued up to the 18th century. Sometimes there were independent rulers in Bengal in the likes of the Ilyas Shahi and Husain Shahi dynasties, while at other times they ruled on behalf of the imperial seat of Delhi.
From the 15th century, the Europeans -- Portuguese, Dutch, French and British traders – exerted an economic influence over the region. British political rule over the region began in 1757 when the last Muslim ruler of Bengal Nawab Siraj-ud-Daulah was defeated at the Battle of Palashi.