In this new book Tadhg Ó hAnnracháin invites us to regard the individuals and communities who moved from, to and across Ireland between 1580 and 1685 as ‘confessional migrants’, drawing attention to the fact that movement, rather than sedentariness, was the default condition for the majority of the early modern population, and that this condition was fundamentally influenced by religion.

The questions at the heart of the book concern the shaping of Ireland's divided religious landscape; the continuous influence of Catholicism in a state in which the established Church ‘dominated political and cultural power’ (p. 3); and the impossibility for any of the three confessions (Catholic, established Church and Presbyterianism) to establish a monopoly on clerical education and distribution.

Aiming to advance our understanding of the role of movement on the religious changes of the early modern period, Ó hAnnracháin centres on Ireland as a significant case study to demonstrate that ‘long-term and short-term mobility of people was a fundamental constitutive process in the religious transformation’ (p. 4). Whilst focusing on a specific geographic area, Ó hAnnracháin's analysis includes a variety of forms of movement that were not forced or immediately driven by religion, be they professional, educational, economic or even quotidian. This enables him, chapter after chapter, to expose how religion ‘informed, influenced, and structured … shaped the possibilities, challenges, and opportunities’ that the migrants confronted and how credal identity functioned as a ‘vital structuring element’ of mobility experiences and practices (p. 321).

The book is divided into two parts. The first constitutes a synoptic investigation of the development of the confessional communities in Ireland. The actual material movement of people is explored through the migratory experiences of the Catholic secular and regular clergy (chapters i–ii), Catholic laity (chapter iii), established Church (chapter iv) and Protestant Nonconformists (chapter v). Ó hAnnracháin highlights the influence of the clergy formed in transnational contexts in the development of confessional positions and migratory experiences are seen as critical to shaping a committed Catholic clergy and hierarchy who created a Church that maintained a consistent influence throughout the century (pp. 55, 78–9). Migration is also regarded as the ‘fundamental constitutive process’ of the Protestant community (p. 98), whose identity was shaped by the opportunities that conformism presented, in economic, political and administrative terms, as well as by the threats posed by living in a country whose population was overwhelmingly Catholic. The third chapter provides an exciting exploration of the dialectic between confessional, political, economic and social factors by focusing on the laity and internal migration. The interaction of religious and non-religious factors is further examined in the last chapter of this section which is dedicated to lay and clerical migrants from Scotland. Here Ó hAnnracháin draws on compelling evidence of mobility driven by disciplinary interventions (pp. 172–3), but all of the chapters in this section are rich in new archival findings through which he restores a vivid and fascinating account of the profound impact of migration on various communities, and social and professional groups.

Part ii is dedicated to the intellectual and metaphoric dimensions of mobility; it examines images and practices of mobility as identity markers (chapters vi and vii) and Catholic and Protestant texts as the product of migrant experiences (chapters viii and ix).

Chapter vi demonstrates the ubiquity of metaphorical readings of biblical accounts across the three confessions, with Exodus as the single most fertile source of imagery and comparisons. That biblical inspirations could be read identically irrespective of confessional adherence, Ó hAnnracháin notes, indicates the ‘crucial importance of understanding practice rather than merely beliefs’ as the grounding of confessional divisions in the island (p. 221). The next chapter explores the forms of mobility intrinsic to religious practice and highlights ‘the act of going together to a specified location of worship’ (p. 223) as a type of confessional mobility deserving of attention. Small-scale mobility emerges as ubiquitous, constant and a critical ingredient in forming confessional community identities, especially in a sectarian context where the movement was often clandestine and furtive. The two final chapters are complementary analyses of Catholic and Protestant works. In chapter viii Ó hAnnracháin analyses what he considers the foundational texts that helped shape a sense of Catholic identity that continued in later works. He offers an illuminating analysis of the evolving conceptualisation of the ‘notion of an essentialist Catholic identity’ (p. 284) and of Irish Catholics as a meritorious nation victim of heretical oppression as a portrayal intended to make the Irish cause a transnational concern. The texts analysed in chapter ix are taken to embody different aspects of migrant identity in the Protestant literary production. An interesting comparison later in the chapter is drawn between the reading of history in Temple's The Irish rebellion and in Lombard's De regno Hiberniae, but the first two authors, Sir James Ussher and Sir James Ware, are examples that by Ó hAnnracháin's own admission fit somewhat uneasily within the group, since the former was not a migrant and the latter not a confessional writer. The section indeed raises fascinating points such as Ussher's ‘vital positioning of identity’ as qualitatively different from that of genuine migrants (p. 291), and Ware's ‘non-polemically confrontational confessional scholarship’ with its implicit ‘assertion of authority’ over native Irish sources (p. 293), but these are treated very briefly and Ussher's and Ware's joint effort as editors of two migrant texts, Spenser's View and Hanmer's Chronicle, is not mentioned.

In this rich and admirable work, Ó hAnnracháin manages to bring out and to explain to the reader the dynamics underlying the shaping of confessional identities, which are extremely difficult to uncover. These processes were not only intellectual, but also material, grounded in the reality of daily life and religious practice. His perceptive analysis adds the role of transnational networks to our understanding of the resilience of Catholicism and its resistance to the Reformation in Ireland, whilst it points towards important further avenues for research, which make the book a highly rewarding read for anyone interested in Ireland, confessionalisation, church history and the early modern clergy and educational system.