Roman tribal reservations

Which, at least in certain parts of north Africa, persisted to the late Empire and beyond; in townships (uici) and the great villas which in the northern provinces were quite as important a facet of the economic and social process of Romanization as were the cities. In mountain areas, such as exist in north Africa (the Kabylie and Aures) and Isauria in southern Asia Minor, lived enclaves of mountain folk hardly touched by Roman civilization but a threat to it if economic conditions turned against them, for then they would descend on the agricultural territories of Roman cities. On the desert fringes to the south and to the east transhumant peoples, and in the north barbarians, moved in and out of Roman territory in a way that paid little regard to the formal barriers of the frontier systems. (Boardman, 1986)