The anxiety over Satan, which led, in a reciprocal relationship of cause and effect, to the relentless persecution of devil-worshippers and acolytes, took hold fully half-way through the Middle Ages. Thus the devil claims an ancient history in Christianity, but the creation of a science of the devil, a demonology, seems to be much more recent. Also, during Christianity's first centuries the possessed could testify to the devil's plans and thus provide the church with useful knowledge. This chapter proposes that the process emerged out of the conjunction, revival and interaction of two ancient ideas: the pact with the devil and devil possession. The first great work of scholastic demonology is probably the lengthy discussion of devils in Thomas Aquinas' treatise On Evil, towards the end of his life. Various juridical bodies could deal with people who invoked demons: numerous episcopal law courts, the court of the Inquisition and ad hoc papal commissions.

The spread of Jews in significant numbers around the Mediterranean, on the other hand, had followed Alexander the Great's conquest of the east, and was consolidated under Greek and then Roman sovereignty. Major Jewish settlements were located in the cities of the Roman provinces of Asia, in Greece and in Egypt. Jewish identities in the ancient Mediterranean varied widely, as might be expected. In the sphere of material culture, burial practices and funerary epigraphy shed light on the Jews' adaptation to their varied diaspora environments. Jews normally adopted the burial patterns and epitaph types used in the wider society. The essence of diaspora circumstances lies in powerlessness more than in power and might always turn to acrimony. This was surely the lesson learnt by Mediterranean Jewry through the half millennium which authors have surveyed of their existence in dispersion. The early Christian communities shared many of the same experiences; they brought to bear on them both old techniques and new.

Almost everyone knows about Christianity in Gaul during the first two or three centuries CE is connected with the Christian communities in Vienne and Lyons in the latter decades of the second century. The precious excerpts, some rather lengthy, of letters written by Christians in Gaul, which Eusebius preserves, and the writings of Irenaeus of Lyons, arguably the important Christian figure of the second century, offer a vivid picture of the remarkable vitality and diversity of these communities. The areas of Gaul in which Christianity appears in the second century CE are marked by the confluence of several forces and peoples. The most important event for the identity of Gaul during the author's period, and for subsequent European history, was the Gallic wars, the eight successive campaigns against Gaul and Britain lead by Julius Caesar between 58 and 50 BCE. The theological seeds that Irenaeus brought with him from Asia clearly flourished into a profound legacy for Christianity in Gaul.

The only late polytheist thinker considered worthy of serious study by historians of philosophy was Plotinus. Since Plotinus' attitude to conventional religion was misunderstood no less by his contemporaries than by modern scholars, it must be emphasized that he was recognized to be a focus of holiness, a holy man. In polytheism, the pursuit of virtue and the spiritual life were primarily the domain of the philosophers. The effect on the broad polytheist community of hearing the street-corner preaching of a wandering Cynic was scarcely to be compared with the regular instruction received by the Christian community from its bishop during the weekly house-church liturgy. The common ground between the Hermetica and the theurgists' sacred texts, the Chaldaean Oracles, lies not just in their Graeco-Oriental character, but also in their acceptance that humans may attain to the divine by many routes, in which cultic practices as well as philosophical intellection have a part.

In exploring the religion of the eighth and ninth centuries, this chapter inevitably explores its society too. Differentiations of religious experience by gender and by status are pointed out. The religion of the laity was as variegated as lay society itself. In surveying the religion of Europe over two centuries of pervasive change, one may well ask what the religion of the urban population of, say, early medieval Milan had in common with that of the new converts in Charlemagne's Saxony. Baptism provides an answer. Baptism distinguished Christians from non-Christians, the fideles from the pagani. Social status affected the way people participated in ecclesiastical celebrations. For the rich, festivals such as Christmas were opportunities to bedeck themselves in their finest apparel. In the course of the eighth and ninth centuries, the clergy of the Christian church took a steadily growing part in shaping the ritual and liturgy which encompassed so many aspects of human existence.