“Somebody who doubts, feuds with or breaches international law itself, unclothes himself of humanity.”1 – These strong and almost pathetic words originate from Heinrich von Gagern, a famous liberal politician in mid-19th century Germany, expressed in his treatise about international law. The 1840 quote refers to a specific phenomenon, namely the negation of international law. Gagern was only one of many scholars who attacked positions of doubt and denial towards international law. Since approximately 1800 jurists, Staatswissenschaftler, theologians, and politicians intensively reevaluated the theoretical foundations of the European law of nations. Around this time, new terms like “Leugner des Völkerrechts” (in German) or “deniers of international law” appeared the first time and addressed those scholars who were supposed to disclaim the legal normativity of international law. In the course of the 19th century the doctrine of international law was subject to manifold changes. Positive sources became a fundamental tool to construct the discipline, the steady emerge of States and their increased relations were in the focus of contemporary treatises whose quantity rose rapidly. New societies and journals were founded, one could say that the discipline of international law underwent a process of institutionalization.2 The appearance of terms like Leugner or deniers of international law has to be considered in this context of institutional evolution. In the second half of the 19th century such wording received a strongly negative connotation and framed a mostly heterogeneous group of scholars. It was referring to eminent academics like Georg Wilhelm Friedrich Hegel or John Austin but also to nationalistic or positivistic perspectives. In this sense, the label of denial was solely an external attribution, none of the alleged scholars identified themselves with that term. The main theory of this paper – and also of my thesis in legal history – is that this stigmatization and exclusion of the “deniers of international law” contributes to the institutionalization of the discipline of international law. It was the reverse side of the inclusion that academically took place. In order to demonstrate this hypothesis I want to focus on German and English doctrinal sources of international law during the second half of the 19th century. Examining those sources does not exhaust in juxtaposing them. Rather, I consider those sources as an output of the contemporary discourse which by inclusion and exclusion constructs and ultimately manifests power to shape the scholarly discipline of international law. Therefore, I will apply methods of intellectual and discourse history as well as Begriffsgeschichte. Eventually, the institutionalization of international law scholarship comes along with the inclusion of manifold theoretical positions. Incompatible approaches were not only excluded in the way of classical logic,3 but deliberately devaluated in a jurisprudential and moral sense. My paper should question the history of terms like Leugner or deniers, depict the contemporary discourse, and consider mechanisms of inclusion and exclusion in the field of international law. The discussion of inclusion and exclusion is still relevant today: The incorporation of non-Western doctrines into a global international law scholarship like e.g. the newly arising Chinese stance4 or the difficulties in dealing with the so-called New Wars and their protagonists rejecting international humanitarian law (IHL)5 express the challenges for a globally accepted normative order in the 21st century. The perspective on the 19th century “European” law of nations – back then strongly influenced by Western actors and systems of thought – and its institutional construction might provide answers.