Islam arrived during the 6th-7th century AD and became dominant gradually since the early 13th century with the conquests led by Bakhtiyar Khalji as well as activities of Sunni missionaries such as Shah Jalal in the region. The country's early documented history featured successions of Hindu and Buddhist kingdoms and empires, vying for regional dominance. Civilisational history of Bangladesh previously known as East Bengal, dates back over four millennia, to the Chalcolithic.
