Until this point, Native Americans had exclusively used the land. In 1866, after the American Civil War, the federal government required new treaties with the tribes that had supported the Confederacy and forced them into land and other concessions. As a result of the Reconstruction Treaties, The Five Civilized Tribes were required to emancipate their slaves and offer them full citizenship in the tribes if they wanted to stay in the Nations. This forced many of the tribes in Indian Territory into making concessions.