Questions of national identity have become pivotal for peacekeepers, policy-makers and scholars. This book illustrates how centuries-old dynastic traditions have been replaced in the modern era by nationalist and ethnic identity movements. The book delineates three epochal changes in the international system: from the medieval, feudal-theocratic order to the dynastic-sovereign system in the 16th century; the territorial sovereign system in the 17th century; and finally, after the American and French Revolutions, the national sovereign system. The book re-examines a broad spectrum of international conflicts in terms of the shifting sands of state identities through time. Arguing for the need to make a clear distinction between nation and state, it shows how an understanding of this dichotomy can help forecast the development of new states over time. Ultimately, the book presents a theoretical model that accounts for human agency as an integral component of national systems.