Beginning in the early-nineteenth century, the British increasingly sought to impose British culture upon the Indians through religion, education, language, and the law.  The British also pursued a policy of territorial expansion within India during the early and middle decades of the nineteenth century.  From the 1820s into the 1840s, this was sometimes accomplished by military engagements, while from 1848 through 1854, four native states were annexed when their rulers died without heirs.  

In 1856, the British viceroy, Lord Dalhousie, deposed the allegedly corrupt ruler of Oudh (in north-central India), and annexed his kingdom even though he had legitimate heirs.  That shift in British policy made every native Indian state vulnerable to annexation.  The trends of cultural and territorial imperialism combined with other factors to produce a very tense situation by 1857.  

The trigger for the rebellion was the rumor that a new type of paper cartridge was greased with animal fat, which was religiously offensive to Indian soldiers in the British armed forces.  The cartridges had to be bitten before use, so grease from cattle would violate religious restrictions of the Hindus, and grease from swine, that of the Muslims.  

Although British officials withdrew the cartridges, violence erupted in May 1857 when native garrisons mutinied against the British Army, hoping to restore the Mogul emperor, Bahadur Shah II, to power.  Since native soldiers constituted over 95% of the British military in India, they were able to amass a sizable army.  However, religious and cultural divisions among the Indians prevented their unity, with the Sihks in the Punjab, for example, remaining loyal to the British.

Colin Campbell (pictured here) was appointed as the British commander in charge of suppressing the Indian rebellion.  He had previously served the British Army in the War of 1812 in the United States, the Opium War (1842) in China, and the Second Sikh War (1848-1849) in India.  Although some criticized his tactics in 1857-1858 as overly cautious, he lost few men and was able to quash the revolt in a few months.  

The fighting was limited mainly to Allahabad, Delhi, Lucknow, Meerut, and other places in the Ganges Valley of northern India, although there were also skirmishes in Madras (southeast), Bombay (west-central), and the Punjab (northwest).  In the early summer of 1857, the rebels had quickly seized Delhi and Lucknow, to which the British laid seize.  In September, the British were able to reoccupy Delhi fully, but did not recapture Lucknow until March 1858.  A final uprising in central India was put down in April.  

In appreciation for Campbell's military leadership, Queen Victoria granted him a peerage as Baron Clyde and an annual pension.  In August 1858, the British government dissolved the East India Company and assumed direct rule over India through the new position of secretary of state for India.  The percentage of British in the Indian armed forces was increased significantly.  The rebellion and its suppression did irreparable harm to the already worsening relations between the British and the Indians.