ABSTRACT
Cities, increasingly dominated by and identified with their bishops, continued, therefore, to constitute the heartland of Constantine's Christian empire. At the same time, the nature of any 'city-based' church had been inevitably modified by developments both within and outside the Christian community. Of all the features of the Christian religion calculated to impress a man of Constantine's experience and ambition, the most striking may have been the increasing eminence of the urban bishop. The successful transition from small groups of teachers and disciples to the commanding authority of a single pastor, symbolized in Rome by the changes that took place between the time of Hippolytus and the time of Fabian, did much to prepare churchmen for their 'triumph'. As accounts by the historian Ammianus Marcellinus reveal, the bishops of Rome were now thrown much more into the arms of an aristocracy that was becoming, at the same time, increasingly frustrated by its isolation and impotence.
