The Irish contribution to the church in early medieval Britain is rightly famous. It is also one of the many examples of the interconnectedness of the peoples and cultures of Ireland and Britain during the medieval period. Yet, with the notable exception of St. Patrick, the influence of Britons and Picts on the early Irish Church is scantily documented, little studied, and poorly understood. The title of Oisín Plumb's book suggests that it will address this gap in the scholarship. In fact, the focus of the book is simultaneously somewhat broader and narrower than this. It is broader because a historical analysis of the impact of Pictish and British migrants on the early Irish Church is only one of the book's concerns, the other being depictions of the same process in later hagiography (19). It is narrower because, although the title refers to Picts and Britons, the author is specifically concerned only with northern Britons, those who resided north of the kingdoms of the Angles and Saxons but south of the Picts and Gaels and whose lands were subsequently incorporated into the kingdom of Scotland.

The book comprises eight chapters, including the introduction and conclusion. Chapter 1 outlines the central topic and contextualizes it in light, first, of the better-known history of migration from Ireland to northern Britain and, second, in relation to the medieval history of Scotland (16–18). Popular views of Scottish history highlight the Irish origins of both the medieval royal dynasty and—with particular reference to Columba and Iona—the Scottish church. Plumb's goal in writing this book seems at least in part to have been shaped by a desire to show that “Scotland” was an exporter as well as a recipient of ecclesiastical influencers. The problem with this approach, however, is that the kingdom of Scotland did not exist during the period under examination. Nonetheless, this Scottish perspective has shaped various aspects of the book. Plumb's desire to distinguish the influence of northern Britons from that of their southern compatriots, for instance, would be difficult to justify on other grounds, as it is not reflective of the content of the sources. See also the author's anachronistic reference to “Scottish Dalriada” (103), though this is not the only instance where imprecise terminology creates problems of interpretation; the use of the term “northern British” to refer to Gaels and Picts from the north of Britain, rather than only for Britons, is a case in point (131).

Chapter 2 provides an overview of the textual sources drawn on, including annals, martyrologies, and various hagiographical texts. Plumb's focus is on attempting to identify named individual migrants, meaning that more general approaches to assessing the British and Pictish impact on the early Church are not discussed. There is no mention, for instance, of the British monasteries known to have existed in early Ireland (though there is mention of their English equivalents [32]) or of the evidence for British influence on Hiberno-Latin.

The following three chapters comprise “case studies” (20) concerned with named individuals who are either depicted in the sources as Pictish or British, or who can potentially be identified as such, and who may have been active in ecclesiastical affairs in early medieval Ireland. Chapter 3 focuses on figures associated in the sources with St. Patrick, either as disciples or family members. Chapter 4 reexamines the evidence relating to the saint or saints known as Uinniau/Finnian. And chapter 5 is largely concerned with the individuals named in a vernacular Irish poem beginning “The seven beautiful sons of Oéngus,” which asserts that the brothers migrated to Ireland and established monasteries there. These chapters were clearly the result of painstaking labor, locating references to the named individuals across a variety of sources of different genres, for which future scholars interested in these figures will be very grateful.

Chapter 6 attempts to identify three “‘channels’ of migration” (139) between northern Britain and Ireland based on the foregoing discussion. One of these, hardly surprisingly, is focused on the Columban network of churches headed by Iona but spanning Ireland and much of northern Britain. The other two are the northern Pictish zone and the territory of the northern Britons. Unfortunately, the networks that linked these regions to Ireland are not outlined in any detail; neither are the practicalities of travel or the specific regions in Ireland with which they were associated. There is no reason to doubt that multiple channels of communication existed between Ireland and various parts of Britain. But the case presented here for the special status of the northern Pictish zone and the territory of the northern Britons as having “particularly tangible and significant links” (139) requires further development.

Chapter 7 takes a different approach to what precedes it, examining the evolution of the “migration narrative” in medieval hagiographical texts. In some ways, this is the strongest part of the book; Plumb argues that the attribution of British origins to figures who were supposedly active in the early Irish church in later hagiographical texts was shaped by concerns in their authors’ own time. He points out, for instance, that some local, Irish saints may have been given British origins in order to forge an association with St. Patrick. As a result, he argues, references to ecclesiastical migration from Britain were more popular in some periods than at others, depending on contemporary concerns.

This chapter highlights a tension at the heart of the book between the author's desire to say something about the early history of the Irish church and the nature of his sources. Perhaps the clearest example of this is the discussion of the poem on the “Seven Brothers.” The only extant copy of this poem is in a twelfth-century manuscript, and Plumb does not challenge its editor's assessment of the language as “distinctly late” (104). In chapter 5, however, he attempts to identify the seven individuals named in the poem as historical migrants from northern Britain. In fairness, Plumb acknowledges that little if anything can be said with certainty about the individuals named in the poem. The same is largely true of the other case studies, which are likewise reliant in many instances on patchy evidence from much later than the period when the supposed migrants lived. As a result, thought-provoking as some of its discussion of hagiographical texts undoubtedly is, the book ultimately offers only tenuous conclusions about the influence of Picts and Britons in the early medieval Irish church.