The motivation behind this readable new book on the conversion to Christianity of the British Isles was twofold: the author's perceived need for an up-to-date review of the theme, and his own wish to explore the reasons for the adoption of Christianity by the rural poor. The second aspect was stimulated by R.I. Moore's conviction, as set out in The Origins of European Dissent (2nd edn, 1983), that there is insufficient (historical) evidence to provide a clear answer. Lambert accepts that his task of covering the period up to the end of the fifth century was facilitated by the appearance, in particular, of A.C. Thomas, Christianity in Roman Britain to AD500 (1981, 1985; also covering Ireland), as well as by M. Henig, Religion in Roman Britain (1984). The dates of these works suggest that the idea for the book lies in the late 1980s. To some extent, it is a long-overdue replacement — published almost exactly a century later! — for Christianity in Early Britain by the Welsh church historian Hugh Williams (1912), to whom it is dedicated.

The author, who has won acclaim for works on the Cathars and on medieval heresy, also takes an approach that is primarily historical, but has been able to benefit from the vast amount of archaeological information gathered since 1912, as well as a more refined understanding of the mechanics of the conversion process. Given the themes that L. explores, it is perhaps surprising that he did not apparently consult P. Brown's The Rise of Western Christendom (2nd edn, 2003), which articulated a convincing hypothesis for how conversion of the pagani was achieved; that is, not just through the appeal of instant forgiveness of sins, but also by compromise and in stages, in allowing converts to retain some of their existing local beliefs. Pagan rituals were replicated within a new, Christian context (e.g. the Water Newton plaques) and pagan sites often reused. Brown also considered that the survival of remnants of Romano-British Christianity into early Anglo-Saxon England made the process a simpler one. L. is, however, aware that the appeal of a Roman and Christian identity, with its benefits for controlling and stabilising societies, encouraged its adoption by those in power. He also suggests that compassion for suffering, involving a strong narrative presented effectively by missionaries, was a key factor in terms of recruiting popular adherents. These were ‘troubled, desperate times’, in which Christianity afforded some consolation.

A work of this scale has required enormous labour, and it is perhaps unsurprising that not all secondary sources that might have assisted the author have been consulted. Apart from Brown's various works, there is no mention of T. Charles-Edwards' edited volume After Rome (2003), covering some of the same ground (though the index refers to this particular author, most of the page references are erroneously to works by A.C. Thomas!). There is in fact little indication that L. has read much about mainland Europe in the fourth to sixth centuries, even though so much archaeological research has taken place there. At least, there is mention of the significant early monastery at Portmahomack in north-east Scotland (M. Carver, Portmahomack, Monastery of the Picts (2008)). Other recent publications, including D. Petts, Pagan and Christian (2011), now a key theoretical text on archaeology and belief, and the proceedings of the 2004 conference on The Archaeology of the Early Medieval Celtic Churches (edited by N. Edwards (2009)), appeared too late to be assimilated. This second volume sets out some of the many achievements of recent archaeological research in Ireland, Wales and Scotland, employing the multi-disciplinary approach first advocated by A.C. Thomas. Despite these omissions, L. has achieved a generally convincing narrative, steering a careful course between the Scylla of the dubious historical sources and the Charybdis of how to read archaeological evidence for belief-systems.

Only three of the eight chapters are concerned with the Roman and sub-Roman periods. L. covers much of the ground previously discussed by Thomas, and in subsequent books by D. Watts (1991, 1998), F. Mawer (1995), and D. Petts (2003). Some controversial ideas do not find favour: possibly his longue durée perspective encourages him to recognise those that carry the evidence too far. For instance, he rejects W.H.C. Frend's view — published in a series of papers, including one in this journal (23 (1992), 121–31) — that Christianity essentially ‘failed’ in Roman Britain. Rather, he concurs with Thomas's view that enough ‘vitality’ survived in the north and west of Britain to allow it to adapt to the needs of the ‘simple rural societies’ of the next few centuries. But he also considers that Thomas exaggerated the extent to which Christianity had penetrated into British society in the fourth and fifth centuries. A rare, striking variation from his usual adoption of the consensus view is his preference for the Severn estuary, rather than south-west Scotland, as Patrick's home region. L. also commends Henig's work for the way in which it both presented the initial introduction of Christianity as one of several eastern religions, which met the need for spiritual values and care better than paganism did, as well as providing some security at a time of political upheaval in the fifth and sixth centuries. L. considers that Christianity offered a more positive outlook than paganism, and confidence in a glorious afterlife. Of course, this is still a matter for speculation, and the archaeological evidence can be read in various ways. The conversion of Britain continued as a long, slow process for several centuries, but it is not within the scope of this journal to review the post-Roman content of the book in any detail.

In summary, this is a valuable single-volume introduction to a critical aspect of those difficult centuries, well-written and engaging, and — on the whole — carefully edited. It is a huge achievement, and this reviewer looks forward to the issue of a revised edition, perhaps one incorporating more of the results of work published in the past decade.