Part one looks at how Christianity was forced to find new ways of distinguishing itself and at the uncertainties in defining "Christian" raised by the "conversion" of figures such as the rhetorician Victorinus and the poet Ausonius. "The image of a society neatly divided into 'Christian' and 'pagan' is the creation of late fourth-century Christians... . [Paganism] existed only in the minds, and, increasingly, the speech-habits, of Christians." Markus presents some of the arguments and debates, between protagonists such as Pelagius, Jerome, Jovinian, and Augustine around the end of the fourth century, over the nature of Christian perfection (the merits of virginity and asceticism against those of marriage and sexuality) and the role of monasteries and monks.
Part two describes how the cult of the martyrs formed a critical link between the present and the past, and how Christianity appropriated existing elements in forming its own sacred calendar. It also looks at different Christian attitudes to secular festivals and banquets and civic games and ceremonies, at Augustine's changing position and at Pope Leo's contribution to the destruction of a neutral "secular" category between Christian and pagan.
In part three Markus turns to concepts of place, both literal and metaphorical. Christianity overcame early fears of pagan holy places to create a new religious topography, centred on Christian history and on churches and relics and pilgrimage routes. In Gaul the influence of Cassian and Salvian and Lerins-trained clergy blurred the boundaries between the monastic and pastoral and spread ascetic ideology into broader society; but things were different in Africa, under Vandal domination, and Italy, where secular high culture survived till the end of the sixth century. Markus concludes: "the massive secularity of John Chrysotom's and of Augustine's world had drained out of Gregory's. There was little room for the secular in it".