This chapter traces the historical foundations and evolving nature of sovereignty from the 1648 Peace of Westphalia to the challenges posed by globalization and the digital age. It begins by examining the classical Westphalian model, which enshrined territorial integrity and non-intervention as core principles of international order. While this model provided the legal and normative bedrock of the interstate system, its rigidity has been increasingly tested by global interdependence, cyberthreats, extraterritorial data flows, and the disruptive influence of emerging technologies. The chapter explores how globalization diluted absolute state control, and how the digital revolution further complicates traditional sovereignty by introducing transnational digital actors, algorithmic governance, and jurisdictional dilemmas. The rise of Big Tech companies, once thought to operate autonomously, is revealed to be deeply entangled with national interests and strategic objectives, exemplifying the emergence of a technopolar world. Here, sovereignty is no longer solely about controlling physical territory, but also about asserting authority over data, algorithms, and cognitive spaces. The chapter concludes by framing this transformation as a shift toward “Sovereignty 2.0,” where digital autonomy, cyber resilience, and algorithmic capacity become essential components of state power and legitimacy in the twenty-first-century international system.