Chapter 6 circles back to the question of what we understand property rights to mean, earlier chapters having made a general case for property rights as a lens through which to study sovereignty and having addressed the question of who is the sovereign who holds those rights. The chapter looks at the roots of different aspects of contemporary sovereign rights in both Roman law and English contract law. It looks at what these different traditions of property have to say about sovereignty with respect to both domestic politics and international relations, and how they interact with other ideas that legitimate the modern state such as popular sovereignty and nationalism. It connects the Roman tradition with a national interest in autonomy, and the English tradition with a national interest in multilateralism. It highlights the conceptual tensions between these traditions as practiced in contemporary international relations.