Why did the Westphalian system arise and what are its principles?

The Westphalian system arose in the mid-17th century following the Peace of Westphalia treaties (1648), which ended the Thirty Years' War in Europe. It established the principles of state sovereignty, non-interference in the internal affairs of other states, and the legal equality of states. This framework emphasized the importance of territorial integrity and the right of states to govern themselves without external intervention, laying the foundation for modern international relations and the nation-state system.