@juergen_hubert You might consider the Guduf (Gudupe), a small tribe of the Fali people residing along the border of northeastern Nigeria and Chad. Many tribes objected to domination by the Bornu and Hausa emirates, and later the Fulani (Fulbe), the dominant ethnic group in North Central Africa. During conflict in the 1800’s tribes including the Guduf fled to the Mandara Mountains, hills and valleys.