The Subsidiary Alliance, a diplomatic strategy employed by the British East India Company, was introduced by Lord Wellesley in Awadh in 1801. The Subsidiary Alliance was a form of alliance between the East India Company and Indian princely states. Under this arrangement:

1. The princely state had to accept a British resident at its court.
2. The state's armed forces were to be maintained by the British, and a British force (subsidiary force) would be stationed within the state.
3. The state would not enter into any alliance with other powers without British approval.
4. The state would cede control of its foreign affairs to the British.

The introduction of the Subsidiary Alliance in Awadh was part of Lord Wellesley's broader policy to strengthen British influence and control over various regions in India. It allowed the British to maintain a significant presence in the internal affairs of the Indian states, ultimately serving the interests of the East India Company.

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