In 1866 the federal government forced the tribes that had allied with the Confederacy into new Reconstruction Treaties. Most of the land in central and western Indian Territory was ceded to the government. Some of the land was given to other tribes, but the central part, the so-called Unassigned Lands, remained with the government. Another concession allowed railroads to cross Indian lands. Furthermore, the practice of slavery was outlawed. Some nations were integrated racially with their slaves, but other nations were extremely hostile to the former slaves and wanted them exiled from their territory. It was also during this time that the policy of the federal government gradually shifted from Indian removal and relocation to one of assimilation.