ʻUmar II’s vast correspondence with governors is examined for the discussion of Islamization and acculturation. From the caliph’s point of view, these two processes had to be regulated and the dilemma was how to formulate a policy that was both in line with Islamic ethics and, at the same time, controlling Islamization by setting a high entrance bar for the converts. The struggle against acculturation attempted to preserve Muslim political dominance by controlling the administration.