Peace of Westphalia #

Pair of treaties signed in October 1648 in the Westphalian cities of Osnabrück and Münster, ending the Thirty Years' War and reshaping European political order. ¹

Components #

• Treaty of Osnabrück — between Sweden and the Holy Roman Empire.
• Treaty of Münster — between France and the Holy Roman Empire, plus recognition of the Dutch Republic.

Key Terms #

• Recognition of the Dutch Republic and the Swiss Confederacy as independent.
• Religious parity extended to Calvinists (the 1555 Peace of Augsburg had only recognized Catholicism and Lutheranism).
• Territorial gains: Sweden (Western Pomerania, Bremen-Verden); Brandenburg-Prussia (Eastern Pomerania); France (parts of Alsace including the Décapole and Sundgau).
• Formalized the fragmentation of the Holy Roman Empire into roughly 300 sovereign entities.

Legacy #

The treaties are credited with establishing the principle of cuius regio, eius religio extended into a broader principle of state sovereignty and non-interference — often called the "Westphalian system." Strictly speaking, the treaties affirmed these ideas more than they invented them, but the term is firmly attached to 1648 in international relations discourse.

Linked #

• Thirty Years' War
• Holy Roman Empire
• Dutch Republic

Sources #

¹ wikipedia-thirty-years-war-2026-06-14.md