British-issued Enfield rifle cartridges, which soldiers had to bite open, were rumored to be greased with animal fat offensive to both Hindu and Muslim soldiers. Discontent simmering in early March 1857 among sepoy regiments in northern India became one of the immediate sparks for the widespread rebellion against East India Company rule that erupted the following May.
The Enfield rifle, newly issued to sepoy regiments of the Bengal Army, required soldiers to bite off the end of a paper cartridge greased with tallow before loading. Rumors spread rapidly through cantonments that the grease came from cow fat, sacred to Hindus, and pig fat, forbidden to Muslims, turning a logistical detail into a supposed act of religious contamination.
By early March 1857, sepoys at several garrisons were refusing orders connected to the new rifles, and British officers dismissed the unrest as superstition rather than a genuine crisis. The grievance tapped into much deeper anxieties among Indian soldiers about forced conversion, annexation policies, and the erosion of their status under Company rule.
What began as isolated refusals and courts-martial escalated within weeks. By May, mutiny at Meerut ignited what the British called the Sepoy Mutiny and Indians increasingly remember as the first war of independence, a rebellion that reshaped colonial rule and led directly to the British Crown assuming direct control of India in 1858.