How superficial the conversion of the Berbers was may be judged from the fact that when the pious ʻUmar b. ʻAbd al-ʻAzīz in A.H. 100 (A.D. 718) appointed Ismāʻīl b. ʻAbd Allāh governor of North Africa, ten learned theologians were sent with him to instruct the Muslim Berbers in the ordinances of their faith, since up to that time they do not seem to have recognised that their new religion forbade to them indulgence in wine. The new governor is said to have shown great zeal in inviting the Berbers to accept Islam, but the statement that his efforts were crowned with such success that not a single Berber remained unconverted is certainly not correct. [1029] For the conversion of the Berbers was undoubtedly the work of several centuries; even to the present day they retain many of their primitive institutions which are in opposition to Muslim law. [1030] Islam took no firm root among them until it assumed the form of a national movement and became connected with the establishment of native dynasties, under which many Berbers came within the pale of Islam who before had looked upon the acceptance of this faith as a sign of loss of political independence. Of these various changes of political condition it is not the place to speak here, but in a history of Muslim propaganda the rise of the Almoravids deserves special mention as a great national movement that attracted a great many of the Berber tribes to join the Muslim community. In the early part of the eleventh century, Yaḥyạ̄ b. Ibrāhīm, a chief of the Ṣanhāja, one of the Berber tribes of the Sahara, on his return from a pilgrimage to Mecca, sought in the religious centres of Northern Africa for a learned and pious teacher, who should accompany him as a missionary of Islam to his benighted and ignorant tribesmen: at first he found it difficult to find a man willing to leave his scholarly retreat and brave the dangers of the Sahara, but at length he met in ʻAbd Allāh b. Yāsīn the fit person, bold enough to undertake so difficult a mission, pious and austere in his life, and learned in theology, law and other sciences. So far back as the ninth century the preachers of Islam had made their way among the Berbers of the Sahara and established among them the religion of the Prophet, but this faith had found very little acceptance there, and ʻAbd Allāh b. Yāsīn found even the professed Muslims to be very lax in their religious observances and given up to all kinds of vicious practices. He ardently threw himself into the task of converting them to the right path and instructing them in the duties of religion; but the sternness with which he rebuked their vices and sought to reform their conduct, alienated their sympathies from him, and the ill-success of his mission almost drove him to abandon this stiff-necked people and devote his efforts to the conversion of the Sudan. Being persuaded, however, not to desert the work he had once undertaken, he retired with such disciples as his preaching had