After the Great Revolution the British Imperialism first tried to rule over their colony by "divide and rule" policy and made a drastic step towards the division of Bengal with a view to creat a administrative division of Bengal and a province with a majority of Muslim Population i.e. the Eastern Bengal.They put an argument that the Bengal Presidency is too large for one Governor to administer.The provinces of Bengal and Assam were reconstituted so as to form two provinces of manageable size.Western Bengal , with a population of 54 million (42 million Hindus and 9 million Muslims), and Eastern bengal and Assam with a population of 31 million (12 million Hindus and 18 million Muslims). The territory to be transferred frm bengal to the new province consisted of the districts of Chittagong and Dhaka Divisions, Rajshahi Divisions excluding Darjeeling, and the district of Malda.
Curzon ,the then viceroy, sent the proposal to London on feb. 1905. The secretary of state for India, St. John Brodrich sanctioned it in June , and the proclamation of the formation of the new province was issued in Sept. The province of Bengal and Assam came into being on Oct. 16, 1905.
Incidentally, the partition went in favor of the Muslims. Before the Partition, western Bengal , being the first area to come under western influence , was developed and Industrialised. It was a striking contrast to the eastern part where the Muslim peasantry was crushed under the Hindu landlords, the river system was infested with pirates, and very few funds were allocated for education. It was dreaded as a place of banishment. The partition helped boost Bengali literature and language; efforts were also made towards the social, economic and educational uplift of the Muslims.