In this article, I have tried to analyze Turkey's participation, following the collapse of the Ottoman state, into the European centered International state system. The article also examines the change in Turkey's different polity, sovereignty, national building-identity, economy, democracy, law and order, and national and international law. The first part covers the emergence, development and expansion of the Westphalian Order. After the Imperial wars, and the end of the colonial era, the coming of the new postcolonial members also enhanced the international system of states as the center of global order, adopting the sovereign nation state system in their international institutions too. Later on, as a result, the expansion of international society promoted internationalization, regionalization, globalization and a post-Westphalian order in Europe. In a nutshell, in Turkey, the history of the classical national, state, and popular, democratic and pluralist sovereignty discussions have also been elaborated in legal texts up to the present day.