Overview

Over a four-year period, the warring parties of the Thirty Years’ War (the Holy Roman Empire, France, and Sweden) were actively negotiating at Osnabrück and Münster in Westphalia. The end of the war was not brought about by one treaty, but instead by a group of treaties, collectively named the Peace of Westphalia. The three treaties involved were the Peace of Münster (between the Dutch Republic and the Kingdom of Spain), the Treaty of Münster (between the Holy Roman Emperor and France and their respective allies), and the Treaty of Osnabrück (between the Holy Roman Empire and Sweden and their respective allies).

The Ratification of the Treaty of Münster, 1648

The Treaty of Münster between the Holy Roman Emperor and France was one of three treaties that made up the Peace of Westphalia.

Painting of a large group of men overlooking a table containing the Treaty of Münster.

These treaties ended both the Thirty Years’ War (1618–1648) in the Holy Roman Empire and the Eighty Years’ War (1568–1648) between Spain and the Dutch Republic, with Spain formally recognizing the independence of the Dutch Republic.

The peace negotiations involved a total of 109 delegations representing European powers, including Holy Roman Emperor Ferdinand III, Philip IV of Spain, the Kingdom of France, the Swedish Empire, the Dutch Republic, the princes of the Holy Roman Empire, and sovereigns of the free imperial cities.

The Terms of the Peace Settlement

Along with ending open warfare between the belligerents, the Peace of Westphalia established several important tenets and agreements:

• The power taken by Ferdinand III in contravention of the Holy Roman Empire’s constitution was stripped and returned to the rulers of the Imperial States.
• All parties would recognize the Peace of Augsburg of 1555, in which each prince would have the right to determine the religion of his own state, the options being Catholicism, Lutheranism, and now Calvinism. This affirmed the principle of cuius regio, eius religio (Whose realm, his religion).
• Christians living in principalities where their denomination was not the established church were guaranteed the right to practice their faith in public during allotted hours and in private at their will.
• General recognition of the exclusive sovereignty of each party over its lands, people, and agents abroad, and responsibility for the warlike acts of any of its citizens or agents. Issuance of unrestricted letters of marque and reprisal to privateers was forbidden.

There were also several territorial adjustments brought about by the peace settlements. For example, the independence of Switzerland from the empire was formally recognized. France came out of the war in a far better position than any of the other participants. France retained the control of the Bishoprics of Metz, Toul, and Verdun near Lorraine, received the cities of the Décapole in Alsace and the city of Pignerol near the Spanish Duchy of Milan. Sweden received Western Pomerania, Wismar, and the Prince-Bishoprics of Bremen and Verden as hereditary fiefs, thus gaining a seat and vote in the Imperial Diet of the Holy Roman Empire. Barriers to trade and commerce erected during the war were also abolished, and a degree of free navigation was guaranteed on the Rhine.

The Holy Roman Empire in 1648

After the Peace of Westphalia, each prince of a given Imperial State would have the right to determine the religion of his own state, the options being Catholicism, Lutheranism, and Calvinism.

A map of the Holy Roman Empire in 1648, including all of the Imperial States.

Impact and Legacy

The treaty did not entirely end conflicts arising out of the Thirty Years’ War. Fighting continued between France and Spain until the Treaty of the Pyrenees in 1659. Nevertheless, it did settle many outstanding European issues of the time. Some of the principles developed at Westphalia, especially those relating to respecting the boundaries of sovereign states and non-interference in their domestic affairs, became central to the world order that developed over the following centuries, and remain in effect today. Many of the imperial territories established in the Peace of Westphalia later became the sovereign nation-states of modern Europe.

The Peace of Westphalia established the precedent of peaces established by diplomatic congress, and a new system of political order in central Europe, later called Westphalian sovereignty, based upon the concept of co-existing sovereign states. Inter-state aggression was to be held in check by a balance of power. A norm was established against interference in another state’s domestic affairs. As European influence spread across the globe, these Westphalian principles, especially the concept of sovereign states, became central to international law and to the prevailing world order.

Europe in 1648

A simplified map of Europe in 1648, showing the new borders established after the Peace of Westphalia.