Jonathan Michael Gray opens his fascinating book with the bold statement: “The English Reformation was as much about oaths as it was about Henry's marriage, succession, and headship over the English Church” (1). Everyone familiar with the period is acquainted with the oaths of succession and supremacy that Henry VIII had tendered to his subjects in the mid-1530s, but Gray's work goes much further, examining “the plethora of different professions Henry employed” and demonstrating that oaths were “crucial to the implementation of and response to the Henrician Reformation” (51, 4).

Gray argues that historians have overlooked oaths “because they misunderstand the nature and importance of oaths in the sixteenth century” (8). Chapter 1 explores the medieval Catholic understanding of oath taking as well as Protestant modification of that tradition. Despite some disagreements, such as the reformers’ rejection of oaths sworn by the mass or on relics, “the differences between Catholics and Protestants were minor when it came to oaths,” for both groups took properly administered and sworn oaths very seriously, indeed conceiving them as a form of worship acknowledging God's power and authority (18).

In chapters 2 and 3, Gray examines the wide range of oaths and subscriptions Henry tendered to his subjects during the 1530s, “a number of distinct professions of different strengths that varied in form, content, and extent of administration depending on Henry's target subject group” (52). The author has carefully scoured the sources to reconstruct the details and context of many such oaths, which the existing scholarship has not always distinguished. One of the most interesting insights of the book is that Henry was motivated to administer such oaths because of his growing awareness that many of his subjects, particularly bishops, friars, monks, and teachers at the universities, had previously sworn oaths to the pope that undermined royal authority (105).

Chapter 4 explores the widely varying ways in which Henry's subjects responded to the oaths tendered to them. The vast majority of English people swore without protest, some tried to avoid or qualify their oaths with protestations, conditional clauses, and equivocation, while secret dissimulation was presumably far more common among critics of the regime, although far more difficult to detect, both by the king's officers and subsequent historians (130–131). This analysis is particularly important because oaths were one of the primary ways in which subjects interacted with the government and the implementation of its agenda.

The next two chapters explore the potential weaknesses of the Henrician regime's use of oaths. Chapter 5 focuses on the extensive use of oaths by those involved in the Pilgrimage of Grace. Gray demonstrates that “the oath of succession both invited and required the pilgrims of 1536 to incorporate oaths into the centre of their rebellion” (153). Interestingly, the oaths the pilgrims administered were just as comprehensive, geographically and socially, as those tendered by the state. Chapter 6 examines the ways in which evangelicals navigated oaths, particularly the adjurations often required in heresy hearings. As with all the oaths of the Reformation period, the situation was more complex than simply agreeing or refusing to swear an oath. Gray's nuanced analysis reveals that “the prosecution of heresy and resistance to this prosecution was more a process of negotiation than it was one of simple enforcement and defiance” (200).

In his conclusion, Gray makes use of a striking metaphor to explain the consequences of Henry's decision to use oaths so extensively: “Oaths in the Henrician Reformation were like nuclear weapons in the Cold War. . . . Oaths engendered more oaths,” both during Henry's reign and during the reigns of his successors (205). However, although the power of oaths could be used to legitimize the regime's policies, that power also cut both ways. Gray asserts: “By forcing a person to make his own decision and by teaching a person that his decision affected his own salvation, oaths were the training grounds of individualism” (214). In the long run, the swearing of oaths empowered subjects more than it did the government, although the overuse of oaths probably contributed to their devaluation over time as well.

Throughout the book, Gray effectively engages with major debates within the existing scholarship on the English Reformation. Indeed, by making oaths the lens through which he explores the period, he offers new clarity about both how the Reformation was implemented and how these monumental changes were experienced and received, testing “the extent to which the English people embraced [Whig], resisted [revisionist], or acquiesced [post-revisionist] to the Reformation” (11). Both students new to the field of English Reformation studies and specialists on the period will find this highly readable and insightful work a valuable addition to their libraries.