Diplomatic History: The Early Foundations of International Relations

Long before international relations became a structured academic discipline with its own theories, models, and university departments, the study of how states dealt with one another rested almost entirely in the hands of historians. They recorded treaties, wars, and the manoeuvres of kings and ambassadors, building a vast archive of who did what to whom and when. This period, known as the Diplomatic History Stage, stretched from 1648 to 1919 and forms the very first chapter in the story of how we came to study world politics. Understanding it helps us see why early scholarship on global affairs looked so different from the analytical, theory-driven discipline we know today.

What was the Diplomatic History Stage? 🔗

The Diplomatic History Stage refers to the earliest phase in the evolution of international relations (IR) as a field of inquiry. It is conventionally dated from the Peace of Westphalia in 1648 to the end of the First World War in 1919. During these roughly 270 years, there was no organised or systematic discipline of IR within universities. Instead, the subject was scattered across courses in history, law, and theology, which produced superficial and unsystematic early efforts at understanding international affairs.

The defining feature of this stage was the dominance of historians rather than political scientists. These scholars approached state interactions the way they approached any other historical subject: by gathering documents, establishing chronology, and narrating events in sequence. The result was a body of work that was rich in detail but thin in analysis. It told you what happened, but rarely explained why it happened or what general patterns might be at work.

Why 1648 marks the beginning 🔗

The choice of 1648 as a starting point is no accident. The Peace of Westphalia was a series of treaties signed in the German cities of Münster and Osnabrück that ended the Thirty Years’ War in the Holy Roman Empire and the Eighty Years’ War between Spain and the Dutch Republic. These settlements are widely credited with establishing the foundation of the modern state system. They articulated the principle that each state holds sovereignty over its own territory and domestic affairs, free from outside interference, and that every state, regardless of size, is equal under international law.

This was a turning point. Before 1648, political authority in Europe was fragmented and overlapping, shared among emperors, kings, princes, and the Church with no clear hierarchy. After Westphalia, the territorial sovereign state became the central unit of international life. The influential thinker Hans Morgenthau later observed that the 1648 settlement made the territorial state the cornerstone of the modern state system. Because states became the building blocks of world politics, scholars naturally organised their study of international affairs around these sovereign units and the relations between them.

How historians studied state interactions 🔗

The scholarship of this era was overwhelmingly descriptive and chronological. Historians focused on documenting the diplomatic record: the negotiation of treaties, the formation and collapse of alliances, the outbreak and conclusion of wars, and the personalities of the statesmen who shaped these events. The method was essentially narrative. Scholars arranged facts in the order they occurred and described them faithfully, treating diplomacy as a sequence of episodes to be chronicled rather than a system to be explained.

This approach had genuine value. It produced detailed and accurate accounts of past events, preserved primary documents, and gave later generations a reliable record of how states had actually behaved. Diplomatic historians were careful researchers who took the archive seriously. The problem was not their accuracy but the narrow scope of their questions.

The focus on the state system and national interest 🔗

The intellectual centre of this stage was the state system itself. Scholars organised their thinking around sovereign states pursuing their national interests, and much of the writing concerned the great powers of Europe. The dominant theme running through the era was the balance of power, the idea that major states sought to maintain an equilibrium so that no single power or coalition could dominate the continent. This balancing produced shifting alliances, territorial adjustments, and frequent military interventions, all of which gave historians an endless supply of events to record.

Two great peace settlements illustrate how this worked in practice and gave diplomatic historians their richest material. The first was Westphalia in 1648. The second came after the Napoleonic Wars, when the Congress of Vienna of 1814-1815 convened to redraw Europe’s boundaries and rebuild the balance of power. Chaired by the Austrian statesman Klemens von Metternich, the Congress reduced France to its pre-revolutionary frontiers without destroying it as a great power, settled disputes over Poland and Saxony, and produced a comprehensive Final Act in June 1815.

The Concert of Europe and nineteenth-century diplomacy 🔗

The Vienna settlement gave birth to the Concert of Europe, a system in which the five major powers, Britain, France, Austria, Prussia, and Russia, managed international affairs through periodic conferences and consultations. This congress system aimed to preserve the post-Napoleonic order, suppress revolutionary challenges, and prevent another continent-wide war. It is often credited with helping Europe avoid a major general conflict for nearly a century after 1815, until the system finally broke down with the outbreak of the First World War in 1914.

The Concert also refined the actual machinery of diplomacy. The Final Act of Vienna, amended at the Congress of Aix-la-Chapelle in 1818, established formal classes of diplomatic missions and orderly rules for signing treaties, replacing the cumbersome older method of exchanging notes between scattered capitals. For diplomatic historians, the nineteenth century was therefore a treasure trove: congresses, conferences, alliances, and crises that could be catalogued and narrated in great detail.

The limitations of the diplomatic history approach 🔗

For all the detail it produced, the Diplomatic History Stage suffered from serious shortcomings as a way of studying international relations. These limitations are precisely what later scholars reacted against, and they explain why the discipline eventually moved in a very different direction.

Description without analysis 🔗

The most important weakness was the absence of causal analysis. Historians of this era described what states did but rarely explained why. They documented that a war broke out or an alliance was formed, but they generally did not search for the underlying forces, recurring patterns, or general laws that might account for such behaviour. The work answered the question “what happened?” far better than it answered “why does this kind of thing happen?” Without causal explanation, the writing could not build toward broader understanding.

Neglect of contemporary events 🔗

A second limitation was the focus on the past at the expense of the present. Because the approach was historical, scholars tended to study events that were comfortably distant, where the documents were complete and the outcomes already known. They largely ignored the analysis of contemporary affairs. This made the field poorly equipped to comment on the pressing international problems of its own day or to offer guidance to those actually conducting foreign policy.

Lack of scientific rigour and theory 🔗

Finally, the stage lacked theoretical development and scientific method. There was no systematic effort to construct concepts, frameworks, or testable propositions that could be applied across different cases. The predominance of historical and diplomatic writing actually crowded out the growth of analytical and theoretical studies. One of the few early attempts to treat world politics as a distinct academic subject was the pioneering work of Paul S. Reinsch, who delivered lectures on world politics at the University of Wisconsin around 1900, but such exceptions only highlighted how undeveloped the field remained.

Why this stage still matters 🔗

It would be a mistake to dismiss the Diplomatic History Stage simply because it lacked the analytical sophistication of modern IR. This period performed an essential function: it built the foundation on which everything that followed was constructed.

First, it established the basic subject matter of the discipline. By focusing on sovereign states, the balance of power, treaties, and alliances, diplomatic historians defined the core concerns that IR scholars still study today. Second, it preserved an enormous archive of accurate historical record, the raw data that later theorists would draw upon when testing their ideas. Theory needs evidence, and the diplomatic historians supplied it in abundance.

Third, the very limitations of the stage created the demand for something better. The shock of the First World War, a catastrophe that descriptive history had failed to anticipate or prevent, pushed scholars toward studying contemporary events and, eventually, toward building genuine theory. The transition to the Current Events Stage after 1919, and later to the Scientific Stage after 1945, was in large part a response to the gaps left by diplomatic history. In that sense, the early foundations did exactly what foundations are supposed to do. They held up the structure that came after, even though they were never meant to be the whole building.

The Westphalian principle of sovereignty that emerged at the start of this stage remains so durable that it is enshrined in the United Nations Charter today, which holds that the organisation may not intervene in matters essentially within a state’s domestic jurisdiction. The descriptive method may have been superseded, but many of the ideas first organised during the Diplomatic History Stage continue to shape how states interact on the world stage.

What do you think? If diplomatic historians had spent more energy explaining the causes of war rather than simply recording it, could the discipline of international relations have helped prevent the catastrophe of 1914? And in an age of globalisation and shared challenges that cross borders, does the Westphalian idea of absolute state sovereignty still serve us well, or has it begun to outlive its usefulness?

References

1. https://www.britannica.com/event/Peace-of-Westphalia
2. https://en.wikipedia.org/wiki/Westphalian_system
3. https://courses.lumenlearning.com/atd-herkimer-westerncivilization/chapter/the-peace-of-westphalia-and-sovereignty/
4. https://opil.ouplaw.com/display/10.1093/law:epil/9780199231690/law-9780199231690-e739
5. https://en.wikipedia.org/wiki/International_relations_(1648%E2%80%931814)
6. https://www.britannica.com/event/Congress-of-Vienna/Decisions-of-the-congress
7. https://en.wikipedia.org/wiki/Concert_of_Europe
8. https://www.britannica.com/topic/diplomacy/The-Concert-of-Europe-to-the-outbreak-of-World-War-I
9. https://www.studocu.com/in/document/amity-university/international-relation/evolution-of-international-relations/124310355