" Despite the common perception in the West, the Muslim conquerors did not force conversion upon the conquered peoples; indeed, they did not even encourage it. The fact is that the financial and social advantages of being an Arab Muslim in the eighth and ninth centuries were such that Islam quickly became an élite clique, which a non-Arab could join only through a complex process that involved becoming first the client of an Arab. "

― Reza Aslan , No God but God: The Origins, Evolution and Future of Islam