For much of the 19th century, Aceh's independence had been guaranteed by the Anglo-Dutch Treaty of 1824 and its status as a protectorate of the Ottoman Empire since the 16th century. During the 1820s, Aceh became a regional political and commercial power, supplying half of the world's pepper, which increased the revenues and influence of local feudal rajas.Growing European and American demand for pepper led to a series of diplomatic skirmishes between the British, French and Americans. During the reign of Sultan Alauddin Ibrahim Mansur Syah (1838–1870), the Aceh Sultanate brought the regional rajas under its control and extended its domain over the east coast.However, this southward trend clashed with the northwards expansion of Dutch colonialism in Sumatra.
Following the 1869 opening of the Suez Canal and changing shipping routes, the British and Dutch signed the 1871 Anglo-Dutch Treaty of Sumatra which ended British territorial claims to Sumatra, allowing the Dutch a free hand within their sphere of influence in Maritime Southeast Asia while handing them the responsibility to check piracy. In return, Britain gained control of the Dutch Gold Coast in Africa and equal commercial rights in Siak.Dutch territorial ambitions in Aceh were fuelled by a desire to exploit its natural resources, especially black pepper and oil, and to eliminate an independent native state player. The Dutch also sought to ward off rival colonial powers that had ambitions in Southeast Asia, particularly the British and the Frenc