The Wellesley-Onís Treaty was a treaty negotiated by Arthur Wellesley of the British Empire and Spanish foreign minister Luis de Onís. The First Seminole War between the British Empire and Seminole Indians in East Florida was started by Seminole aid for the American Insurgency against the British. This campaign, led by Sir Edward Pakenham, caused the effective control of the British in East Florida. Not wishing war with Britain on top of the rebellions in their colonies, the Spanish opened negotiations with the British.