This book is co-authored by three political scientists. The Medieval Review defines the focus and scope of its reviews as “all areas of Medieval Studies, a field it interprets as broadly as possible.” This vision of its ambit fits well with the history of the field of Medieval Studies as a whole, which has long had a reputation for openly embracing interdisciplinarity. That said, political science--and the data-driven social sciences more generally--has typically not been central to the field’s self-conception. I suspect many of the readers of this review do not anxiously await the latest issues of American Political Science Review, Review of Economics and Statistics, and the British Journal of Criminology--only three examples from the social sciences of journals that have published articles on medieval Europe in recent years. Along these lines, readers may also be unaware that the book reviewed here is just one of several monographs about the Middle Ages to be published by political scientists in the past few years. Others include Jørgen Møller and Jonathan Stavnskær Doucette, The Catholic Church and European State Formation, AD 1000-1500 (Oxford University Press, 2022); Anna Grzymała-Busse, Sacred Foundations: The Religious and Medieval Roots of the European State (Princeton University Press, 2023); and Bruce Bueno de Mesquita, The Invention of Power: Popes, Kings, and the Birth of the West (PublicAffairs, 2022). This book is therefore not some sort of strange outlier. It belongs to a large body of work on medieval Europe in the social sciences--a body of work that runs parallel to the more humanities-based version of Medieval Studies with which most self-identified “medievalists” are probably more familiar.

For those not trained in the field, political science’s vision of the Middle Ages can often look like a foreign land. Some well-known historians are referenced in the book under review here--Chris Wickham, Robert Bartlett, and Thomas Bisson, for example--but the work’s main interlocutors are other social scientists. Charles Tilly, Francis Fukuyama, and Michael Mann, all of whom discuss medieval Europe in the context of global political developments more broadly conceived, have important roles to play in shaping this book’s theoretical framework. As a result, the reader must be comfortable with a level of abstraction that is uncommon within the more traditional, humanistic branches of Medieval Studies. Indeed, while the subject matter of this book is similar in some ways to that of Björn Weiler’s Paths to Kingship in Medieval Latin Europe, c. 950-1200 (Cambridge University Press, 2021), there is nothing similar about their approaches. There is no thick description, close reading of medieval sources, and nuanced analysis of individual cases here. Instead, the focus is on the datasets. One of these is comprised of over 700 rulers in 27 European states between 1000 and 1799 and consists of information about the length of their reigns, their marriages, their children and other relatives, and how their reigns ended. A second dataset consists of information about the dates and lengths of the wars fought by European states, both internal and external, during the same period; a third is comprised of the dates of parliamentary meetings at the regnal level in those same European states. While the authors do occasionally discuss specific rulers and events, these are only used as examples to explain broader trends.

The main argument of the book is this: “the gradual adoption of primogeniture hereditary monarchy helped to mitigate the problems of succession, leading to greater political stability and allowing for the development of the modern European territorial states” (2). While the authors do acknowledge at the outset that “primogeniture has been the cause of much evil well into modern times” (vii), they nevertheless insist that there is a direct correlation between primogeniture and effective state-building efforts in Europe, which they describe as being much more successful than state-building efforts elsewhere around the globe. Historians tend to caution against situating medieval history into this sort of simplistic mode of teleological thinking, but to be fair, both in this book and many other works by political scientists, the goal is to draw lessons from history, not to study history for its own sake.

The book’s argument unfolds across ten chapters. Chapter 1, which is the introduction, lays out the main arguments. Chapter 2 explores the various problems that can arise at moments of succession in autocratic regimes and considers the pros and cons of different succession strategies, including primogeniture, ultimogeniture and partible inheritance. Chapter 3 explains the central concepts with which the authors are working (elites, the people, family and dynasty, the state) and introduces the datasets. Chapter 4 on the origins and spread of primogeniture resurrects the British anthropologist Jack Goody’s flawed argument that “the Church”--a single-minded, Dalek-like actor in this version of history, not an institution comprised of enormous numbers of individuals capable of having different opinions and agendas--systematically forbade polygamy, consanguinity, divorce, and adoption (among other things), because it was to the economic benefit of the Church to narrow the number of possible heirs and to encourage property donations to itself. The period of the Gregorian Reform was, in this version of events, the turning point, after which the Church’s views on inheritance and succession gained the upper hand and began spreading across Europe. According to the authors, this is the reason why primogeniture only became commonplace in Europe from the eleventh century onwards.

With Chapter 5, the authors begin to rely increasingly on their datasets to prove their arguments about the importance of primogeniture. In this chapter, they argue that, while moments of succession tend in general to increase the risk of civil war for a polity, those that practiced primogeniture saw fewer civil wars than those that practiced other forms of succession. Chapter 6 on leader depositions has as its hypothesis that states practicing primogeniture saw fewer rulers deposed than under elective monarchy and agnatic seniority; their data confirms this hypothesis. Chapter 7 focuses on the calling of parliaments and argues that parliaments and “parliament-like institutions” were more likely to be called during periods of succession, but that this likelihood declined as primogeniture began to ensure more stability during these transitional moments. Chapter 8 emphasizes the importance of family groups for creating stability in states practicing primogeniture; both male and female relatives were more likely to be supportive rather than disruptive when there was no question that the eldest son would succeed, in contrast to states with less rigid succession rules. Chapter 9 places the politics of succession in comparative perspective. Specifically, it uses data from Islamic states, which did not practice primogeniture, to show that European states that did practice primogeniture were significantly more politically stable. The chapter is much cagier about pre-modern China, which the authors are forced to acknowledge was one of the most stable states in world history even though primogeniture was not practiced there. Chapter 10, the conclusion, reiterates the main arguments and briefly considers succession in modern states as well as what lessons can be gleaned from the relationship between primogeniture and political stability in European history.

For readers familiar with the rich scholarship on medieval kingship written by historians, some of this book’s arguments may seem more like well-established facts than hypotheses that need to be tested. Medieval historians probably do not need to read this book’s “empirical analyses” to be convinced of “the central role played by kin relationships in medieval and early modern monarchies” (180). Similarly, that Carolingian partible inheritance led to political upheaval in Francia but the Capetian dynasty’s long run of father-son succession brought stability to France is not exactly news. Medievalists may also notice that the strong bias toward polities that had developed into modern-looking European states by 1800 leads the authors to marginalize regions where other types of political communities existed; the Holy Roman Empire, which the authors “stop counting...as a functioning state after the Golden Bull of 1356” (53), is the most obvious example. There are also other types of head-scratching moments. Figure 7.1 (146), for example, which depicts the “Percentage of country-years with parliamentary meetings over time,” shows significantly more meetings of “parliament-like institutions” in Europe in the eleventh century than in any other century between 1000 and 1800, which begs the question of what, at the granular level, does and does not count as a “parliament-like institution” in the authors’ dataset.

Despite these criticisms, I encourage any scholars from the “traditional” fields of Medieval Studies who are interested in politics and succession to read this book. Its approach to the Middle Ages is unquestionably jarring at times; political science has its own jargon and its own ways of constructing arguments, which are very different from those in the humanistic fields of Medieval Studies. Nevertheless, this book, and other recent books on medieval states published by political scientists, call attention to the remarkably large and rich historiography on medieval Europe in the social sciences. We should not underestimate the value of cross-disciplinary dialogue, nor should this scholarship be dismissed by other medievalists simply because it asks very different questions from other work in the field. Indeed, one could argue that some of the shortcomings of this book fall on the shoulders of medieval historians who do not publish their research in forms that political scientists can easily find, access and add to their datasets. As universities continue to hire fewer and fewer scholars in the traditional fields of Medieval Studies, it would behoove medievalists of all stripes to find allies and build bridges wherever we can.