On October 16, 1905, the British Raj, under Viceroy Lord Curzon, formally implemented the Partition of Bengal, dividing the Bengal Presidency into West Bengal (with Bihar and Orissa) and Eastern Bengal & Assam. The official rationale was administrative efficiency: Bengal, with over 78 million people, was seen as too vast to govern effectively.

However, Indian nationalists viewed it as a deliberate “divide and rule” scheme designed to fracture the unity of Hindus and Muslims and weaken the growing independence movement.  Hindu Bengali leaders mobilized public sentiment through mass protests, petitions, and by promoting the Swadeshi Movement — boycotting British goods and encouraging indigenous manufacture. On the day of the partition, many observed mourning, and some tied rakhis between Hindu and Muslim friends as a symbolic gesture of unity. 

Despite fierce opposition, the partition stood for six years. In 1911, the British government, recognising the scale of unrest, annulled the division and reunited Bengal — though the communal fissures it seeded had lasting political repercussions.