This book is about the process by which a religion which had grown up in the Mediterranean world of the Roman empire was diffused among the outsiders whom the Romans referred to as the barbarians; with far-reaching consequences for humankind. [...] The acceptance of Christianity by these outsiders was not simply a matter of confessional change, of religious belief and observance in a narrow sense. It involved, or brought in its wake, a much wider process of cultural change. The conversion of 'barbarian' Europe to Christianity brought Roman and Mediterranean customs and values and habits of thought to the newcomers who were the legatees of the Roman empire. These included, for example, literacy and books and the Latin language and all it opened up; Roman notions about law, authority, property and government; the habits of living in towns and using coin for exchange; Mediterranean tastes in food, drink and costume; new architectural and artistic conventions. The Germanic successor-states which emerged from the wreckage of the empire--for these are the outsiders with whom we shall be initially concerned--accepted Christianity and in so doing embraced a cultural totality which was Romanitas, 'Roman-ness'. It was particularly significant that this occurred at a time when two other processes were shattering the cultural unity of the Mediterranean world. One of these was the withdrawal into herself of the eastern, Byzantine, Orthodox half of the former Roman empire. The other was the irruption of Islam into the Mediterranean and the resultant hiving off of its eastern and southern shores into an alien culture. The cultural unity of the Mediterranean disappeared for ever. But what had been harvested from the classical world and transplanted with Christianity into a northern seedbed germinated there, sprouted and grew into a new civilization, one which indeed owed much to the Mediterranean but was distinctively its own: western European Christendom. The growth of Christendom decisively affected the character of European culture and thereby, because of European dominance in human affairs for several centuries before the twentieth, the civilization of our world. That is why the coming of Christianity to north-western Europe is worth examining, and why this book has been written.

Christendom--late antique, early medieval, high medieval--knew that it was attractive to outsiders by reason of its wealth and power. These widespread perceptions furnished the activists in the diffusion of Christianity with their trump cards. They also possessed an unshakeable self-confidence founded upon those heady and tremendous assurances about God's purposes which they had read in the Bible. Riches and order confirmed and strengthened their confidence. They could play these cards again and again, and almost always with success because manifestly the Christians were almost always the winners and the pagans the losers. [...]

These perceptions by outsiders were justified. Christian spokesman were not indulging in deceitful boasts or sleight of hand. It is still inadequately appreciated that Christian Europe in the early Middle Ages was both wealthy and well managed. The view that the early medieval economy was in some sense 'primitive' or 'under developed', long ago abandoned by medievalists, is still widespread. It deserves the strongest possible emphasis that such a judgement is without foundation. Medieval Christendom was densely settled--the population was almost certainly much higher than the usual estimates that have been made--and efficiently exploited. Furthermore, it commanded, partly by inheritance from a Roman or pre-Roman past, partly by means of fertile improvisation, orderly structures and techniques of power (family, community, hierarchies, kingship, literacy, law, taxation and so forth) which were demonstrable effective, and which were above all flexible and adaptable to novel social circumstances.

Not the least remarkable of such ordered structures was the institution of the Christian church.