First defined by Pufendorf as ‘several states that are so connected as to seem to constitute one body but whose members retain sovereignty' ( De sytematibus civitatum 1675), the System of states emerged as Europe transitioned from dynastic empires to absolutist states. But the need to secure the system only became self-evident upon the threat of its destruction by Napoleon. In the 1809 preface to the Manual of the History of the Political System of Europe and its Colonies, A.H.L. Heeren wrote: ‘while the author was thus employed in elaborating the history of the European states system, he himself saw it overthrown in most essential parts….Its history was in fact written upon its ruins.' Out of the Congress of Vienna that ended the Napoleanic wars would come systemic institutions of security, like balance of power, international law, and great power alliances, backed by a common set of norms, values, and customs, all with the goal of maintaining what Ranke called ‘unity in diversity'. Eventually other actors would challenge the international system and its state-centric (not to mention euro-centric) character. National liberation groups, transnational civil society organizations, epistemic communities, and multinational corporations became new important actors. And with the increasing diversity of membership came challenges to the universalism of its western norms. The priority of systemic over state security – as evidenced by the number of times Poland was swallowed up by more powerful states to bring ‘equilibrium' back to the system, or African and Middle-Eastern polities were carved up by imperial powers – was called into question by revolutionary movements. Should freedom and justice for individual actors take priority over the promise of order and viability provided by the system?