TIBESTI  , a mountainous and little known region of the central

Sahara, inhabited by the Tibbu (q.v.) . The country was partly explored in 187o by Gustav Nachtigal; it had not been again visited by Europeans up to 191o, though French officers had reached Borku on its southern borders . By the Anglo-French declaration of the 21St of March 1899 Tibesti was included in the French sphere of influence in North Africa .