The Berber tribes were spread over all these provinces. In the eastern part of Ifrikiya the chief were the tribes of _Hwara_, _Luata_, _Nefusa_, and _Zuagha_: in Central Ifrikiya the _Warghu_ and _Nefzawa_: in western Ifrikiya the _Nefzawa_, _Katama_, _Awraba_, and a number of smaller tribes to the south: the chief tribes of Central Maghrab were the _Zuawa_ (or Zouaves), _Magbrawa_, and _B. Mzab_: and in Farther Maghrab the _B. Wanudin_, _Ghomara_ (in the Rif of Morocco), the _Miknasa_, etc. No satisfactory result has ever been attained by those who have tried to identify the ancient Numidians, Mauritanians, and Gaetuli with existing tribes; evidently, as in Arabia, there have been new groupings and new formations, which forbid the tracing back of the mediaeval tribal divisions to ancient times; perhaps it was Islam which finally rendered permanent the divisions as they existed in the first century of the Hijra. Amongst these Berber tribes were spread the tribes of Arab invaders and settlers which, even in the 10th century A.D. extended in scattered groups from the borders of Egypt to the Atlantic. For the most part each race preserved its own language, the Arabic dialects being distinguished by archaic forms, and a phonology somewhat modified by Berber influences; but there are several instances of Berber tribes which have adopted Arabic, and some of Arabs and mixed groups which have adopted the Berber language. For the most part the Arabs have had no reluctance to mingle with the Berbers, but the attitude of the Berbers varies, and some groups rigidly exclude intermarriage between themselves and the Arabs or any others.