A sepoy was formerly the designation given to an Indian soldier in the service of a European power. In the modern Indian Army, Pakistan Army and Bangladesh Army it remains in use for the rank of private soldier.
In its most common application Sepoy was the term used in the British Indian Army, and earlier in that of the British East India Company, for an infantry private. It is still so used in the modern Indian Army, Pakistan Army and Bangladesh Army. Close to 300,000 sepoys were crucial in securing the subcontinent for the British East India Company. There was widespread mutiny amongst the sepoys of the Bengal Army in the Indian Rebellion of 1857 after it was alleged that the new paper cartridges being issued to them used beef tallow to grease the casing (see "Causes of the Indian Rebellion of 1857").
Following the formation of the French East India Company (Compagnie des Indes) in 1719, companies of Indian sepoys (cipayes) were raised to augment the French and Swiss mercenary troops available. By 1720 the sepoys in French service numbered about 10,000. Although much reduced in numbers, France continued to maintain a Military Corps of Indian Sepoys (corps militaire des cipayes de l'Inde) in Pondichery (now Puducherry) until it was disbanded in 1898 and replaced by a locally recruited gendarmerie.
Sepoys were also recruited in Portuguese India. Some Portuguese sepoys were later sent to serve in other territories of the Portuguese Empire, especially those in Africa. The term "sipaio" (sepoy) was also applied by the Portuguese to African soldiers and African rural police officers.