Peace of Westphalia 1648
The Peace of Westphalia, signed in 1648, ended the Thirty Years’ War and marked a turning point in the development of the modern international system. It established the principles of state sovereignty, territorial integrity, and non-interference in domestic affairs as foundations of international law. The Westphalian system remains a cornerstone of contemporary international relations.
Reference:
Encyclopaedia Britannica – Peace of Westphalia