The purpose of the project is to enhance understanding of the problem of international norm formation: how can ideas about appropriate and legitimate international behavior evolve into institutional and perhaps even legal arrangements? This is accomplished by analyzing the evolution of the practice of arbitration in the modern state system, from the end of the 16th century up to the interwar period. In particular during the 19th century, up until the Hague conferences, the idea of arbitration developed into a principal norm of interstate conflict resolution. This development corresponds to a progressive institutionalization, which culminated at the Hague conferences and the inauguration of the Permanent Court of Arbitration. A central contention of the project is that the development of international norms and institutions is significantly linked to prevailing ideas about the moral purpose of the state. Therefore, theories of international relations can but provide an imperfect account for the problem at hand; we need also to consider the interchange between notions of righteousness in international politics, and ideas about the sources of political legitimacy and authority in general, which is the province of political theory. The objective of the project is thus to develop theoretical knowledge in the as yet not very well cultivated border land between international relations, international law, and political theory.