Excerpts from Books and Wikipedia
"By 702, the Islamic conquest of North Africa was nearly complete. The Berbers, the native North Africans, converted in remarkable numbers. Their tribal structure made conversion a mass event rather than an individual decision; when the leaders of a tribe converted, the rest of the tribe followed. The Arabic realm itself was beginning to cohere a little more tightly under al-Malik’s expert administration. He had already introduced standard currency; he put his brothers, whom he trusted, into the most vital governors’ offices; and he began to construct a new mosque in Jerusalem that would provide a place of worship and pilgrimage even more central than the Ka’aba in Mecca (although Mecca retained its importance). This mosque, the Dome of the Rock, was built on the site of the destroyed Second Temple of the Jews; it protected the rock from which Muhammad was said to have ascended into heaven. Al-Malik also decreed that the Arabic language would be the official language of the empire, something no previous caliph had done. This provided a desperately needed glue for the widely scattered realm." [Bauer: Medieval World, p. 325]