European traders arrived late in the 15th century, and their influence grew until the British East India Company gained control of Bengal following the Battle of Plassey in 1757.[11] The bloody rebellion of 1857, known as the Sepoy Mutiny, resulted in transfer of authority to the crown, with a British viceroy running the administration.[12] During colonial rule, famine racked the Indian subcontinent many times, including the Great Bengal famine of 1943 that claimed 3 million lives.[13]

Between 1905 and 1911, an abortive attempt was made to divide the province of Bengal into two zones, with Dhaka being the capital of the eastern zone.[14] When India was partitioned in 1947, Bengal was partitioned along religious lines (for the majority Muslims), with the western part going to India and the eastern part joining Pakistan as a province called East Bengal (later renamed East Pakistan), with its capital at Dhaka.[15] In 1950, land reform was accomplished in East Bengal with the abolishment of the feudal zamindari system.[16] However, despite the economic and demographic weight of the east, Pakistan's government and military were largely dominated by the upper classes from the west. The Bengali Language Movement of 1952 was the first sign of friction between the two wings of Pakistan.[17] Dissatisfaction with the central government over economic and cultural issues continued to rise through the next decade, during which the Awami League emerged as the political voice of the Bengali-speaking population. It agitated for autonomy in the 1960s, and in 1966, its president Sheikh Mujibur Rahman was jailed; he was released in 1969 after an unprecedented popular uprising.

In 1970, a massive cyclone devastated the coast of East Pakistan, killing up to half a million people,[18] and the central government responded poorly. The Bengali population's anger was compounded when Sheikh Mujibur Rahman, whose Awami League won a majority in Parliament in the 1970 elections,[19] was blocked from taking office. After staging compromise talks with Mujib, President Yahya Khan arrested him on the early hours of March 26, 1971, and launched Operation Searchlight,[20] a sustained military assault on East Pakistan. Yahya's methods were extremely bloody, and the violence of the war resulted in many civilian deaths .[21] Chief targets included intellectuals and Hindus, and about ten million refugees fled to neighbouring India.[22] Estimates of those massacred throughout the war range from three hundred thousand to 3 million.[23]

Before his arrest by the Pakistan Army, Sk. Mujibur Rahman formally declared the independence of Bangladesh and directed everyone to fight till the last soldier of the Pakistan army was evicted from East Pakistan. Awami League leaders set up a government-in-exile in Calcutta, India. The exile government formally took oath at Mujib Nagar in Kustia district of East Pakistan on April 14, 1971 with Tajuddin Ahmad as the first Prime Minister. The Bangladesh Liberation War lasted for nine months. The Bangladesh Forces formed within 11 sectors led by General M.A.G. Osmani consisting of Bengali Regulars and Mukti Bahini conducted a massive guerilla war against the Pakistan Forces with all out support from the Indian Armed Forces. Jointly the Mitro Bahini achieved a decisive victory over Pakistan on December 16, 1971, with Indian Armed Forces taking over 90,000 prisoners of war.