First british came as traders. they looked at our wealth and slowly started with the English east india company. thenĀ  they started annexing kingdoms. some accepted with the british in subsidiary alliance. some rulers did not accept and many wars occurred .unfortunately all wars were won by british. subsidiary states if indian rulers lend their kingdoms, rulers will be given protection. doctrine of lapse states that if the ruler did not have their son the kingdom should be given to the british .like wise they captured the whole india.