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The Treaty of Westphalia: the Origin of International Relations

In 1648, the Treaty of Westphalia ended the Thirty Years War (1618-1648) and the Eighty Years War (1568-1648). However, the main outcome of this peace treaty is much broader than ending two bloody wars. The Treaty of Westphalia is accepted as the beginning of modern international relations since it introduced the concepts of sovereignty, mediation, and diplomacy (Patton, 2019, p. 91). Besides this, the basis of international organisations and the first attempts to codify international law can be found in this treaty. Furthermore, the Treaty of Westphalia stands out for being the first secular Congress that gathered in Europe. This article will discuss these points in detail.

Figure 1: Allegory of the Peace of Westphalia

The Eighty Years War was a struggle for independence by the Habsburg Netherlands (encompassing the border regions of modern Belgium, Luxembourg, France and The Netherlands) from the Spanish crown. After a short-term ceasefire, the war resumed in 1621 (Patton, 2019 p. 92). By that year, the Thirty Years War had already started as an international war in German territory due to religious intolerance (Gross, 1948, p. 21). When the freedom of states to choose their religion, granted by the Peace of Augsburg (1555), was proved insufficient, Protestants sought the support of the Netherlands, England, and France to defend their rights (Sander, 2020, p. 99). The Catholic states, on the other hand, united under the leadership of Bavaria with the support of the Holy Roman Empire (Sander, 2020, p. 99). Thus, the Thirty Years War started as a religious war between Catholics and Protestants, but transformed into a war between the Holy Roman Empire and states seeking independence. When the two wars – the Thirty Years War and the Eighty Years War – coincided, the Netherlands and Spain continued their war on German territory (Sander, 2020, p. 99). The congress that gathered for peace after these long and international wars could be considered the first congress in Europe. Another novelty brought forth by this congress was the separation of problems of state, war, and power from religious issues (Sander, 2020 p. 100). Crucially, the signature of the pope was not regarded as necessary when signing the Treaty of Westphalia.

Figure 2: The Relief of Genoa took place in 1625, during the Thirty Years' War

For the Congress of Westphalia, 96 diplomatic representatives from different entities assembled in two different cities: Münster and Osnabrück (Nathan, 2002, p. 2). While Catholics gathered in Münster with a papal mediator, Protestants, with an imperial representative, met in Osnabrück (Ribard, 1983, p. 367). Diplomats tended not to engage in any sort of compromise quickly (Patton, 2019, p. 93) since none of them wanted to seem weak or to be the cause of a conflict that would be protracted. This lack of consensus resulted in a six-year congress. The negotiations that had been going on between 1642 and 1648 resulted in two treaties: the Osnabrück and Münster Treaties. The summary of these treaties as listed by David Maland, author of Europe at War 1600-1650, is: Entities under the Holy Roman Empire were recognized as independent sovereign states; Calvinism was recognised and protected by the Peace of Augsburg (1555); religion-based conflicts would be resolved by compromise (previously they were decided by a majority of votes); Spain was excluded from the Westphalian settlement and had to bow to the Dutch in all matters (Maland, 1980, p. 183-187). Three features of the Peace of Westphalia that are essential for the construction of modern international relations are religious freedom, the nature of war, and the idea of sovereignty (Patton, 2019, p. 94-97).

Figure 3: The Historical City Hall of Münster

Religious freedom is important because, for Catholics, Protestants, and Lutherans, it had been an ongoing problem both before and after the Treaty of Augsburg. On account of their religious devotion, kings and princes looked after the interests of the papacy in the detriment of their own national interests. As states and principalities viewed their international relations from the perspective of religion, they tended to see those who were not of their same religion as evil. This made it difficult for states to establish good relations with each other. With the Peace of Westphalia, states, free from religious oppression, recognized each other as sovereign entities. Without the oppression of the emperor, Lutherans, Protestants, Calvinists, and Catholics could practice their political power in their own territories (Patton, 2019, p. 95).

Before the Congress of Westphalia, war was the primary tool for solving a conflict. With the Treaty of Westphalia, especially during the Congress, states exercised the diplomatic profession. With the change in perceptions of states toward each other, diplomacy and negotiation emerged as alternatives to war (Patton, 2019, p. 95). Nevertheless, it should be noted that negotiations had been used before this treaty. The differentiating factor of Westphalia was the official recognition of diplomacy. The reason why diplomats were officially recognized by this agreement was that the states accepted each other as sovereign entities. Sovereignty means that the state has legitimate rights over its territory: for instance, declaring war, collecting taxes, and engaging in war-ending negotiations. The German provinces under the Holy Roman Empire had not been able to exercise this type of authority. However, with the peace of Westphalia, provincial princes obtained the mentioned rights. At the same time, this is an indication that the dominance of a central authority, the Holy Roman Empire, which was questioned during the Thirty Years War, was de jure and de facto decreasing. Sovereignty, as established with the Treaty of Westphalia, is still one of the fundamental concepts in international relations today. In addition to sovereignty, other new concepts arising from this treaty are still at the heart of international relations, such as the creation of the United Nations (UN) and other international organizations.

Figure 4: Banquet of the Amsterdam Civic Guard in Celebration of the Peace of Münster

Leo Gross, scholar of international law at Tufts University, refers to the Peace of Westphalia as the first great European charter (Gross, 1948, p. 20). Indeed, there are similarities in basic principles between the UN charter and the Peace of Westphalia. The most prominent being that the UN charter is based on the sovereign equality of states. On the one hand, the Peace of Westphalia granted religious equality and the right to conduct private worship; on the other hand, religious freedom and fundamental human rights are protected under the UN charter. Both charters contain the principle of peaceful settlement of conflicts (Gross, 1948, p. 25). In practical terms, it would not be wrong to say that the starting point of modern international law is, in effect, the Peace of Westphalia (Gross, 1948, p. 26).

To sum up, the Treaty of Westphalia is a milestone in today’s international relations. The most important concepts of modern international relations are found within its lines. With this treaty, interstate relations started to be carried out in a secular framework, and this contributed to the development of interstate relations in an overall more positive manner. In addition, the foundations of modern international law were laid as governments recognized each other's sovereignty. The Treaty of Westphalia marks the end of an era and the beginning of a new one. In this new era, it is possible to find traces of the Peace of Westphalia in treaties, institutions, and states. All of these features make the Treaty of Westphalia fundamental for international relations studies.

Bibliographical References

Gross, L. (1948). The peace of Westphalia, 1648–1948. American Journal of International Law, 42(1), 20-41. Maland, D. (1980) Europe at War 1600-1650. Totowa NJ: Rowman and Littlefield Nathan, J. A. (2002). Soldiers, statecraft, and history: coercive diplomacy and international order. Greenwood Publishing Group. Patton, S. (2019). The Peace of Westphalia and Its Affects on International Relations, Diplomacy, and Foreign Policy. The Histories, 10(1), 5. Ribard, A. (1983). İnsanlığın Tarihi. (E. Başar, Ş. Yalçın, H. Berktay Trans.). İstanbul: Say Kitap Pazarlama Sander, O. (2020). Siyasi tarih: İlkçağlardan 1918'e. İmge Kitabevi.

Visual Sources

Cover Image: Terborch, G. (1648). The Ratification of the Spanish-Dutch Treaty of Münster, 15 May 1648. [Painting]. Retrieved from:

Figure 1: Jordaens, J. (1654). Allegory of the Peace of Westphalia. [Painting]. Retrieved from,today%20is%20not%20appropriately%20named.

Figure 2: De Pereda, A. (1634-1635). The Relief of Genoa by the 2nd Marquis of Santa Cruz. [Painting]. Retrieved from

Figure 3: Historical City Hall of Münster. [Photograph]. Retrieved from

Figure 4: Van Der Helst, B. (1648). Banquet of the Amsterdam Civic Guard in Celebration of the Peace of Münster. [Painting]. Retrieved from


Great breakdown of the events that caused and lead to the Treaty, as well as its implications on the global stage. Maybe a more timeline approach to the exposition of events would improve clarity.


Really enjoyed how you explained the circumstances that led to & allowed the congress of Westphalia to happen. Also, appreciated how you then linked that to modern IR!

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Yaprak Akkaya

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