The early Roman Empire rested on a network of cities, which were capable both of conspicuous expenditure locally, in the form of public buildings, shows and festivals, and of carrying many of the functions of government; but by the fourth century their capacity to perform these roles had drastically declined. Both the capacity and the decline depended in part on the availability or inavailability of the richer classes to undertake expenditures associated with public offices or with liturgies. These remarks are of course mere commonplaces. They have become so, in the first place, because precisely these changes were noted, and the issues relating to them consciously formulated, in the fourth century itself. So Libanius writes in his Funeral Oration for Julian:
He showed the same care also in relation to the councils in the cities, which formerly flourished in both numbers and wealth, but by that time had come to nothing, since their members, except for a very few, had switched course, some into military service, some into the Senate … The remainder were all but sunk, and for the majority of them undertaking public services (to leitourgein) ended in beggary. Yet who does not know that the vitality of its council is the soul of a city ? But Constantius, while in theory aiding the councils, in practice was their enemy, by moving elsewhere men who sought to evade them, and granting illegal exemptions (ateleiai).
Three points should be noted here: Libanius assumes an evolution which was, if not universal, at any rate general throughout the Empire; the crisis is regarded as having been caused by the availability of roles or statuses which offered an alternative to the obligations of city councillors ; and this availability itself is seen as a product of imperial actions, which (as Libanius goes on to say) Julian had taken steps to reverse.