Subsidiary Alliance is a system of ruling a dominated nation. Lord Richard Wellesleyintroduced it in India in the 19th century. At that time, there were local rulers in India. The system worked as follows: The (ruling) British would enter into a contract with a local ruler. This ruler had to accept many conditions; among them was that he would only deal with the British and no other European forces, that he must allow British forces in the territory he ruled, and that he would not declare war without asking the British first