1. Introduction

The modern state system, characterized by sovereign, territorially defined political entities, is a cornerstone of contemporary international relations. It shapes global governance, diplomacy, and the interaction between nations. However, this system is not timeless; it emerged through a long and complex historical process influenced by wars, treaties, philosophical developments, and changing economic and social structures. The evolution of the modern state system can be traced from the decline of medieval political order to the Peace of Westphalia in 1648, and then through subsequent transformations brought by nationalism, industrialization, imperialism, and globalization.