Arthur Vööbus, the pioneering scholar of much Eastern monasticism, wrote that ‘ideas have legs’. This book has demonstrated how ideas about abstention from food, drink, sleep, and wealth, could travel between religions as well as between far distant places in the Graeco-Roman world, though they were often much changed on the journey.Widely varying practices concerning food and sex could be given a new home in Porphyry's philosophical asceticism. Neoplatonist ideas about training for contemplation of the divine could then be deployed in Philos redescription of Jewish practices originally meant to uphold the priestly purity of Israel. From there, amongst other places, they crossed into service within a Christian psychomachy. Within Christianity communal fasts were taken over from Judaism only to be partly turned against their original practitioners. Origen's ascetic theology travelled far across the empire, so that purely regional accounts of monasticism obscure the exegete's profound influence. Regional cultures, on the other hand, proved more or less hospitable to different ascetic ideas. The idea of prayer without work found it hard to get a foothold in urban communities likely to be burdened by its presence. Semi-anchoretic monasticism could only travel a certain distance from the communities which sustained it. Some ideas proved extremely hard to budge, despite the best efforts of eloquent Christian preachers: widowed Christians continued to remarry; while celibate men and women continued to live together for something like two hundred years after we first find them denounced for so doing.

Some ascetic ideas could not find a space within the pages of this book: Manichaean abstention has been the most notable absentee.