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–Cameroon Petroleum Development and Pipeline Project Cameroon, and that the revenues be put towards improving social and economic conditions. Since 1990, President Idriss Deby has been the head of government in Chad, where presidential elections are held every five years. Chad's economy is dependent mainly on agriculture and livestock. It heavily relies on foreign assistance and foreign capital, as well as international investment projects. Because of Chad's landlocked borders, its economy struggles from a lack of resources and instability between rebel groups. The country also serves as a host to thousands of refugees from neighboring Sudan and Central African Republic, as well as many victims of