Although IR scholars have offered various explanations for the origins of sovereignty, the literature is yet to offer a convincing one. Rejecting the hypothesis to locate sovereignty with Westphalia, this paper traces the emergence of sovereignty to two nineteenth century developments: the dominance of the positivist legal theory and the ascendancy of European states over non-European states. Theoretically, this paper integrates critical legal theory and postcolonial theory into international relations theory. The critical legal theory clarifies how three doctrines that constructed sovereignty (state?s ultimate authority, territoriality, recognition) were directly related to the positivist (as opposed to earlier natural) legal theory. The postcolonial theory illuminates how the positivist legal theory?s construction of sovereignty was related to the legitimization of European and delegitimization of non-European political entities. Sovereignty both justified and enabled Europe? domination over non-European political entities. The empirical part of the paper examines the imposition of extraterritoriality (European states? exclusive jurisdiction over their citizens in non-European states) in Japan, China, Turkey, Iran, and Thailand to provide evidence that positivist legal theory?s attempt to conceptualize the interaction of European states? interaction with the non-European political entities crystallized the doctrine of sovereignty. ..PAT.-Unpublished Manuscript [ABSTRACT FROM AUTHOR]