This chapter explores changes in the international system in the first half of the eighteenth century. It throws new light on the balance of power, one of the models most commonly used to describe international relations in the period. Some critics dispute whether this model actually ‘works’ because the balance of power meant different things to different people. However, this chapter describes a particular understanding of what the balance of power meant to a particular group of people at a particular time. It is assumed here that the perceptions of those involved in debates are as revealing as the strategic reality of a situation. Thus, even if there was no objective balance of power, the series of exchanges which assumed its existence are interesting in themselves. Both British and Hanoverian writers and politicians viewed the preservation of the balance of power as the most powerful means to defend the protestant interest and combat the threat posed by universal monarchs, real or imagined.

The focus is on how contemporary writers and thinkers justified their specific understandings of the balance of power, universal monarchy and the protestant interest. Such understandings provide the key to explaining the policies and decisions discussed in later chapters. By addressing a series of objections to the heady mixture of religion and politics, it will become clear why the links between the three concepts contained in the chapter's title have been overlooked previously. It will be important to consider what impact historical conventions about periodisation might have had on the acceptability or viability of a ‘protestant interest’ after the Peace of Westphalia (1648). This will be linked to a discussion of secularisation. The belief that international politics was quickly secularised after 1648 indicates more about the persistence of whiggish myths than historical reality. The historiography of international relations needs to catch up with recent developments in enlightenment studies. The easy distinction made by liberals in our own time between religion and politics may apply in theory to our present situation but it has no place in the eighteenth century.