The Indian Rebellion of 1857 was a major uprising in India in 1857–58 against the rule of the British East India Company, which functioned as a sovereign power on behalf of the British Crown.

In which year did Sepoy Mutiny start and between whom?

Indian Mutiny, also called Sepoy Mutiny or First War of Independence, widespread but unsuccessful rebellion against British rule in India in 1857–59. Begun in Meerut by Indian troops (sepoys) in the service of the British East India Company, it spread to Delhi, Agra, Kanpur, and Lucknow.

Why did the Sepoy Mutiny start?

The mutiny began when sepoys refused to use new rifle cartridges (which were thought to be lubricated with grease containing a mixture of pigs' and cows' lard and thus religiously impure). They were shackled and imprisoned, but their outraged comrades shot their British officers and marched on Delhi.