This book was born from a conference held in July 2000 to mark the beginning of the third Christian millennium, opened by David Hope, Archbishop of York. In accordance with the spirit and energy of early church councils, 55 papers were heard in five days and each evening our indefatigable delegates also attended a party and a public lecture on ‘Heritage and the Holy Land today’. It was an occasion of incomparable enrichment, which brought to light the art and culture of early people of every degree and condition and their preoccupation with fundamental questions about what life is for, and how it should be lived.

Given the venue, the City of York, and the interests of its Department of Archaeology, it is not surprising that in the event a majority of the papers focussed on the experience of northern Europe in the first millennium AD, and this has been the basis of their selection for publication. This book surveys episodes of conversion from the Dingle Peninsula to Estonia and from the Alps to Lapland, and ranges in time from Roman Britain and Gaul in the third and fourth centuries to the conversion of peoples in the Baltic area a thousand years later. In Europe, the cross went north, and also east, as the centuries unrolled and this basic narrative provides the structure of the book. We begin in the Celtic lands, proceed to England and then to the Rhineland and Scandinavia, ending in Estonia where the principal conversion initiative took place in the thirteenth century.

However, to read the conversion story as a narrative does no justice to the complexity of the process, as our authors show. History is written by those who have won power and represent what is orthodox, so the surviving documents extol the achievements of individual missionaries, and emphasise their success. They can also encourage us to believe that the adoption of Christianity, with a hierarchy of bishops and a network of monasteries and churches was somehow irresistible. This perspective paints a picture in which some of the converted got the message early, some later; others did not wholly understand it and mixed it with previous beliefs, but all eventually entered the fold and became as one.

But, as the later history of Christianity shows, wherever the human mind is active diversity is endemic.