Gibbon's other observations on the role of religion in the fall of Rome require rather more attention. They can largely be regrouped into a slightly different formulation. The establishment of the Church had vast logistical implications in terms of the creation of a new category of religious persons (clergy and monks), which necessitated the transfer of very considerable quantities of wealth, to begin with largely of treasure but increasingly of land. Although these developments will scarcely help explain the fall of the west Roman Empire, they will shed a good light on why what had been the Roman World looked very different in 600 than it had three hundred years earlier. Moreover, unlike questions of culture and belief, topics that can be studied in terms of numbers perhaps are more amenable to integration into the broader history of the end of the western Empire. Clergy, ecclesiastical treasure, and Church property do allow some quantitative observations. We will look at these issues in turn.

Let us begin with numbers, and first with Gibbon's image of the bishops fulminating from 1,800 pulpits. This figure can only be guesswork. Mommsen, in fact, reckoned that there were 5,627 civitates (cities and their surrounding districts) in the Roman Empire—and given that many if not all civitates also came to function as dioceses one might conclude that 1,800 bishops is an underestimate. A. H. M. Jones, however, reckoned that there were only about 1,000 cities in the eastern Empire in the days of Justinian, among them there were at least 330 bishoprics in the province of Asia. For the West we do not have comparable figures, though we do know of 114 civitates in Gaul, while Gildas speaks of a further 28 in Britain. We can question the likelihood of there being 28 bishops in Roman Britain, and can certainly agree that whatever Church organization was in existence in the early fifth century was radically disrupted in the course of the following 150 years. Yet across the Channel there were around 130 Merovingian dioceses, few of which are likely to be post-Roman foundations. According to Jones, the documentary evidence suggests that the provinces of North Africa contained around 500 bishoprics.