“Far from marking a rupture with the past, the first two centuries of Islamic history have come to be seen as an extension of late antiquity—if not its triumphant denouement. This is especially true if we regard Muḥammad and the early caliphs as heirs to the Constantinian revolution—especially that distinctive marriage of empire and monotheism that Constantine brought about through his conversion in the fourth century. A by-product of this revolution was the use of state power to promote right belief and purge wrong belief.”