History of Chad Africa's major language groupings south of the Sahara Desert (except Khoisan, which is not considered a valid genetic grouping anyway), i. e. the Afro-Asiatic, Nilo-Saharan and Niger–Congo phyla, originated in prehistoric times in a narrow band between Lake Chad and the Nile Valley. The origins of Chad's peoples, however, remain unclear. Several of the proven archaeological sites have been only partially studied, and other sites of great potential have yet to be mapped. At the end of the 1st millennium AD, the formation of states began across central Chad in the sahelian zone between the desert and the savanna. For
Chad yet occur in Chad. In 2006 and in 2008 rebel forces attempted to take the capital by force, but on both occasions failed. An agreement for the restoration of harmony between Chad and Sudan, signed 15 January 2010, marked the end of a five-year war. The fix in relations led to the Chadian rebels from Sudan returning home, the opening of the border between the two countries after seven years of closure, and the deployment of a joint force to secure the border. In May 2013, security forces in Chad foiled a coup against President Idriss Deby that had been