The senior battalion of what became the 10th Baluch Regiment in 1922, was raised in 1820, as the 2nd (Marine) Battalion 12th Regiment of Bombay Native Infantry. In 1838, as the 24th Regiment of Bombay Native Infantry, it stormed and captured the city of Aden (Yemen) as part of a punitive expedition sent to rid the area of pirates. The 26th Bombay Native Infantry was raised in 1825, as the 2nd Extra Battalion of Bombay Native Infantry, changing its name a year later. In 1843, the British conquered Sindh after defeating the ruling confederacy of Baloch chieftains. General Sir Charles Napier, the British commander, was much impressed by the ferocious courage of his Balochi opponents and decided to recruit them for local service within Sindh. As a result, two irregular battalions of Bombay Army, the 1st and 2nd Belooch (old spelling of Baluch) Battalions were raised in 1844 and 1846 at Karachi. In 1856, the 2nd Belooch Battalion was dispatched to fight in the Persian War in 1856–57, a campaign frequently overshadowed by the events of the Great Indian Rebellion of 1857. Meanwhile, the 1st Belooch Battalion was dispatched on foot across the Sindh desert in May, to join the siege artillery train on its way to Delhi; the only Bombay unit to join the Delhi Field Force. The battalion was brought into line in 1861, for its services in North India and it became the 27th Regiment of Bombay Native Infantry in the post-Mutiny realignment. 2nd Belooch, in the meantime, had qualified for a similar change in status and became the 29th Regiment of Bombay Native Infantry.