The Holy Roman Empire and its complex multi-layered governmental structure have been a frequently researched topic. Yet Christopher Close manages to add a new and much-needed study with his overview of the German and Netherlandish history of early modern alliances. As the title suggests, the book focuses on the complex relations between the Holy Roman Empire and the Low Countries, which in 1488 still formed part of the Burgundian Imperial Circle (Burgundian Kreis) but did not share any other institutions with the Empire. This constellation already illustrates the complexity of the Holy Roman Empire: not only imperial cities and principalities but also Circles all had their own, sometimes overlapping, jurisdictions. Close shows that these different players established and joined alliances for other reasons than just political expediency, such as religion or protection from a possible strong neighbour. The Low Countries provide an excellent example of how religious strife forced the rebellious provinces to forge an alliance against Spain, and ultimately led to the creation of the Dutch Republic.

In his introduction, Close explains the purpose of his monograph as providing a ‘comprehensive and comparative view of early modern leagues’ (5), which ‘links the operation of specific alliances over time to state formation at the local, regional, and national levels’ (5). What becomes clear through this detailed study is how a hierarchical state structure was circumvented through the alliances (also known as leagues), as these could collaborate with every jurisdiction regardless of status. They were meant to safeguard the league’s members’ best interests, whether by armed force or by the mere threat of its existence. These different alliances took up a protective role which individual principalities or imperial cities could not provide on their own. Their political role was significant, as the pledge to protect each other’s interest in often tumultuous time levelled the playing field for all participants, regardless of the size of their territory or the number of inhabitants.

The eight chapters analyse the various alliances in chronological order. While the first chapter deals with the Swabian League (1488-1534) and its political activities, the following chapters focus on more religious-based alliances, including the Schmalkaldic League (1531-1547), the Catholic League (of Neurenberg) (1609-1635), and the Protestant Union (1608-1621), and stress the attempts to balance power play within the Holy Roman Empire. The chapters featuring the examples of the League of Landsberg (1556) and the Low Countries (1566-1609) illustrate how complex multi-confessional alliances could (or could not) function, and created significant political challenges. The final two chapters of the book discuss the religious alliances of the seventeenth century and the influence they had – or strained the relations – during the Thirty Years’ War. By providing a longitudinal overview, Close advances our knowledge of alliance-making significantly.

While the focus is on the Holy Roman Empire, a small part of the book is dedicated to the development of the Dutch Republic. In his fifth chapter, Close discusses the Low Countries, where during the 1570s the Union of Arras and the Union of Utrecht were formed. Especially the Union of Utrecht attracts his attention, as matters of religious practice were left to the separate provinces and should not matter to the union itself. Delegating religion worked well in the Dutch case, whereas it had failed earlier with the League of Landsberg. The Union of Utrecht was successful and became one of the longest-lasting leagues until the end of the eighteenth century. The contrasts described between the League of Landsberg and the Union of Utrecht offer an intriguing analysis of success and failure.

The underlying theme of this book is state formation, by taking a close look at the (de)stabilising role of alliances and their activities on this process. Close provides detailed examples of seemingly small threats to principalities, such as the hostage-taking of messengers and negotiators, being the proverbial straw that breaks the camel’s back. He thus convincingly contextualises and illustrates the necessity of joining and working together within a (religiously oriented) alliance. In doing so, this monograph offers longitudinal overviews of political developments and why certain states did – and others did not – work well together. The role of states, their religious preferences, and interests that needed protection drove them into the arms of potential allies. While the need for alliance-making is thoroughly discussed, the changes this caused to the internal structure of these states is not part of the analysis. Understanding those changes would square the circle of better understanding state formation – under external pressure and threats.

One wonders why Close starts his book with the Swabian League, not taking into account earlier medieval examples of alliances, while he does leap forward to the Princes’ League in 1785. Indeed, why did he not begin his book at a later point, since his examples are predominantly religious-based alliances? The use of specific terminology could also have been discussed in greater detail: why not talk about Landstande instead of Estates, as the latter has an elective connotation? Another minor point of critique is the lack of detailed maps. The two maps which indicate the location of the Low Countries and the Imperial Circles do not provide the reader with enough details to follow the rather complex alliances. Additional maps indicating which principalities or Imperial Cities were part of which league or union would have been a helpful visual aid for the reader and would have reinforced Close’s argument.

This incredibly detailed book is worth reading when one wants to gain in-depth knowledge of the organisation of the Holy Roman Empire and the Dutch Republic, and especially of the ways in which – beyond that formal structure – alliances served to protect one’s lands. This study could also serve as an invitation to conduct more research into the history of alliances elsewhere.