The Residencies of British India were political offices, each managed by a Resident, which dealt with the relations between British India and a large number of princely states.
The Residency system has its origins in the system of subsidiary alliances devised by the British after the Battle of Plassey in 1757, to secure Bengal from attack by deploying East India Company troops of the Bengal Army within friendly Native States. Through this system, the Indian Princes of these Native States were assured of protection from internal and external aggression, through deployment of company troops. In return they had to pay for the maintenance of those troops and also accept a British Resident in their court. The Resident was a senior British official posted in the capital of these Princely States, technically a diplomat but also responsible for keeping the ruler to his alliance. This was seen as a system of indirect rule that was carefully controlled by the British Resident. His role (and all were men) included advising in governance, intervening in succession disputes, and ensuring that the States did not maintain military forces other than for internal policing or else form diplomatic alliances with other States. The Residents attempted to modernize these Native States through promotion of European notions of progressive government.
The first Native States to enter such subsidiary alliances included Arcot, Oudh, and Hyderabad. Before the Rebellion of 1857, the role of the British Resident in Delhi was more important than that of other Residents, because of the tension that existed between the declining Mughal Empire and the emerging power of the East India Company. After the establishment of Crown rule of British India in 1858, the indigenous States ruled by the Indian princes retained their internal autonomy in terms of political and administrative control, while their external relations and defence became the responsibility of the Crown. An area over two-fifths of the Indian subcontinent was administered by native princes, although nothing like such a high proportion in terms of population.