The Peace of Westphalia (Westfälischer Friede, vɛstˈfɛːlɪʃɐ ˈfʁiːdə) is the collective name for two peace treaties signed in October 1648 in the Westphalian cities of Osnabrück and Münster. They ended the Thirty Years' War (1618–1648) and brought peace to the Holy Roman Empire, closing a calamitous period of European history that killed approximately eight million people. Holy Roman Emperor Ferdinand III, the kingdoms of France and Sweden, and their respective allies among the princes of the Holy Roman Empire, participated in the treaties.
The negotiation process was lengthy and complex. Talks took place in two cities, because each side wanted to meet on territory under its own control. A total of 109 delegations arrived to represent the belligerent states, but not all delegations were present at the same time. Two treaties were signed to end the war in the Empire: the Treaty of Münster and the Treaty of Osnabrück. These treaties ended the Thirty Years' War in the Holy Roman Empire, with the Habsburgs (rulers of Austria and Spain) and their Catholic allies on one side, battling the Protestant powers (Sweden and certain Holy Roman principalities) allied with France (though Catholic, strongly anti-Habsburg under King Louis XIV).
Several scholars of international relations have identified the Peace of Westphalia as the origin of principles crucial to modern international relations, collectively known as Westphalian sovereignty. However, some historians have argued against this, suggesting that such views emerged during the nineteenth and twentieth century in relation to concerns about sovereignty during that time.
Europe had been battered by both the Thirty Years' War and the Eighty Years' War, exacting a heavy toll in money and lives. The Eighty Years' War was a prolonged struggle for the independence of the Protestant-majority Dutch Republic (the modern Netherlands), supported by Protestant-majority England, against Catholic-dominated Spain and Portugal. The Thirty Years' War was the most deadly of the European wars of religion, centred on the Holy Roman Empire.