Explanation:

 Partition of Bengal, (1905), division of Bengal carried out by the British viceroy in India, Lord Curzon, despite strong Indian nationalist opposition. It began a transformation of the Indian National Congressfrom a middle-class pressure group into a nationwide mass movement.
Bengal, Bihar, and Orissa had formed a single province of British India since 1765. By 1900 the province had grown too large to handle under a single administration. East Bengal, because of isolation and poor communications, had been neglected in favour of west Bengal and Bihar. Curzon chose one of several schemes for partition: to unite Assam, which had been a part of the province until 1874, with 15 districts of east Bengal and thus form a new province with a population of 31 million. The capital was Dacca (now Dhaka, Bangl.), and the people were mainly Muslim.
The Hindus of west Bengal, who controlled most of Bengal’s commerce and professional and rural life, complained that the Bengali nation would be split in two, making them a minority in a province including the whole of Bihar and Orissa. They regarded the partition as an attempt to strangle nationalism in Bengal, where it was more developed than elsewhere. Agitation against the partition included mass meetings, rural unrest, and a swadeshi (native) movement to boycott the import of British goods. The partition was carried through despite the agitation, and the extreme opposition went underground to form a terrorist movement.
In 1911, the year that the capital was shifted from Calcutta (now Kolkata) to Delhi, east and west Bengal were reunited; Assam again became a chief commissionership, while Bihar and Orissa were separated to form a new province. The aim was to combine appeasement of Bengali sentiment with administrative convenience. This end was achieved for a time, but the Bengali Muslims, having benefitted from partition, were angry and disappointed. This resentment remained throughout the rest of the British period. The final division of Bengal at the partitioning of the subcontinent in 1947, which split Bengal into India in the west and East Pakistan (later Bangladesh) in the east, was accompanied by intense violence.