An interesting information i have read that i would like to share
Between 634 and 870 Islam was transformed from the badge of a small Arab ruling class to the dominant faith of a vast empire that stretched from the western Mediterranean into Central Asia. As a result of this long and grandual peried of conversation, Arab cultures intermingled with indigenous cultures of the conquered peoples to produce islam's fundamental orientations and identities. The Arabic langauge becaome a vehicle for the transmission of high culture, even though the arabs remained a minority for the first time in the history of the Nile-to-Oxus region, a new language of high culture, carrying a great culture florescence, replaced all previous languages of high culture. Trade and taxation replaced booty as the fiscal basis of the muslim state; a nontribal army replaced a tribal one; and centralized empire became a nominal confederation, with all the social dislocation and rivalries those changed imply.