Any three Military Causes of the Revolt.

(1) DISCRIMINATION in pay and promotion — an Indian sepoy was paid far less than a British soldier doing the same duties, and however able he was he could rise no higher than the rank of Subedar. (2) The GENERAL SERVICE ENLISTMENT ACT of 1856, which required every new recruit to serve wherever ordered, including overseas; crossing the sea meant loss of caste for a Hindu. The foreign service allowance (batta) was also withdrawn. (3) The LOSS OF BRITISH PRESTIGE after their reverses in the First Afghan War (1838-42) and the Crimean War, which convinced the sepoys that the British were not invincible; and the immediate provocation of the GREASED CARTRIDGES of the new Enfield rifle, which had to be bitten open and were believed to be greased with the fat of cows and pigs.

One mark per cause. The three strongest are discrimination, the 1856 Act, and the loss of prestige. If you include the greased cartridges, LABEL them as the IMMEDIATE cause — they are the spark rather than an accumulated grievance, and papers often ask for that separately. The Afghan War point is the one most often omitted and psychologically the most telling: the myth of British invincibility had been broken.