Final answer:
The true fact about the Sepoy Mutiny is that the British issued cartridges rumored to be greased with pig and cow fat, offending the religious principles of the sepoys and leading to the uprising.
Step-by-step explanation:
The true statement about the Sepoy Mutiny is that the British hurt the religious sentiments of the Indian soldiers by issuing rifle cartridges that were rumored to be lubricated with pig fat and cow fat. Such substances are forbidden in Islam and Hinduism, causing a rift between the sepoys and the British.
This directly led to the Sepoy Mutiny of 1857, where Indian soldiers rose against British rule, resulting in a violent struggle and severe consequences for both sides.