Fascination with bad people has its own fashions. Two centuries before Augustine's time, African Christians had an obsession with the enemies of true belief who obstinately chose their own perverted way to the truth: “heretics” as they had come to be named. These early heretics, however, had a style of their own. The writings of Tertullian, the pre-eminent Christian ideologue in the Africa of his age, a stern Catonian moralizer, are focussed on his struggles with the enemies of true belief. The names that he provides for them are a guide to identifying the most dangerous of these hostiles as they were perceived at the time. Apart from external non-Christian threats like diviners, fakirs, false seers, astrologers, and Pythagoreans, the most threatening internal enemies of the church were heretics who advocated gnostic versions of Christian truth. Like those of other orthodox activists of the time, Tertullian's battles were waged against dangerous persons who advocated a less material and tangible, a less fleshy nature of the Christian deity. The rather satisfying frisson to this story, in the eyes of some, came when the obstinate and feisty Tertullian was caught in his own ideological trap. He was branded a Montanist, an adherent of one of the other big heresies of his age. Then nothing.

A long and strange interlude extended over the remainder of the third century and most of the fourth when this first fascination with heretics faded. New concerns, such as local and then state-driven persecutions, and the forging of a harder ideology of martyrdom, came to the fore. But in the decades of the 370s and 380s, there was a resurgence of interest in heresy and heretics, and this time it amounted to something more than an obsession. In the world of western Mediterranean Christianity, the general history of writings attacking heresies and heretics can be divided into two broad periods. The first great anti-heretical movement, which included the writings of Irenaeus in Gaul, Hippolytus in Rome, and Tertullian at Carthage, as we have noted, was directed against gnostic attacks on the real material substance of Christ's body. After this initial spate of anti-heretical action, the urgent interest in heresy went dormant for over a century. Then, with sudden force, a second great wave of interest in heretics resurged in the third quarter of the fourth century. Very few of the specifics of the first obsession with heretics made it across the great divide between the two movements. In his treatise written in the mid-360s, Optatus, the Catholic bishop of Milevis, accused Parmenian, the dissident bishop of Carthage, of having introduced into his jeremiad many strange ideas and names of men long forgotten and currently unknown in Africa – men like Marcion, Praxeas, Sabellius, and Valentinus. Optatus was right. These men were long forgotten. The reason for their presence in Parmenian's writings was his use of old literary texts to construct his attack on the Catholics as the “real heretics” of his age. In consequence, as Optatus claimed – scoring a direct hit on his hated rival – Parmenian had dragged a lot of long-forgotten episodes from ancient history, like so many dead fish, into his argument.