In some cases, an enrolled member of a federally recognized tribe may have no documented Native American "blood" (biological descent). Some of the Freedmen of the Cherokee Nation of Oklahoma used to be such members. Following the Civil War, the U.S. government's 1866 treaty with the defeated Cherokee, who had been Confederate allies, required them to free their slaves and to provide the freedmen with citizenship in the tribe. By recent referendum, the Cherokee Nation limited membership to only those people who could show descent from at least one Native American listed on the Dawes Rolls. This excluded nearly 2000 Cherokee Freedmen, who, with their ancestors, had been participating in the tribe for generations. Litigation on this matter continues.