The fusion of Desert and City is one of the most momentous of the changes in the spiritual landscape of Late Antiquity. Cassian had warned his monks to keep away from women and from bishops. His influence on Lerins may have been considerable; but it did not prevent many of its monks, indeed its leaders, from taking on episcopal office. The recruitment of a large section of the Gallic episcopate from the monastic circle of Lerins is only a facet of it. It eased the entry of ascetic ideas into the society and the minds of urban Christians, with still untold consequences for their view of themselves and the world around them. One scholar has written of this ‘flow of talent from the monastic to the pastoral world’ and concluded that the Virtue of monks became less a text-book model of spiritual health for other men, and more of a transfusion into the blood-stream of the whole community'. It would be unwise to press the ‘less’ and the ‘more’: the fact is that the influx of men and the nature of the model for spiritual health both had vast influence. For this reason it is important to plot the change that ascetic ideas themselves underwent.

Such a sketch must begin with Cassian himself, whose ‘Desert’ is in fact a more complex notion than the simple foil to the ‘City’ for which it has so far done duty here.