Gaetulia, ancient district of interior North Africa that in Roman times, at least, was inhabited by wandering tribes, the Gaetuli. The area, not clearly defined, included the southern slopes of the Atlas Mountains, from the Aurès Massif westward as far as the Atlantic; southward it extended to the oases in the northern part of the Sahara. Distinguished from the peoples to the south, the Gaetuli belonged to the Berber-speaking peoples who formed the population of Numidia. These peoples were noted for their horse breeding; they dressed in skins and lived on flesh and milk. The only manufacture connected with their name was that of purple dye. The modern nomadic peoples of the area are probably descended from the Gaetuli.