Focusing on the 1851 International Sanitary Conference, this dissertation analyses an important episode in the international regulation of health, trade, passengers, and cargo in a period of epidemic crisis. It argues that a group of diplomats and physicians appointed to represent 12 European nations instituted a new international forum that extended - and occasionally rivalled - national and local agencies for epidemic governance. Together, delegates endeavoured to establish a common sanitary policy in Europe and in the Orient. By creating shared surveillance and judicial mechanisms - while standardising definitions and practices - delegates aimed to engineer the flow of people, vessels, cargo, and diseases in the Mediterranean region. As a transnational forum, the Conference was a platform where doctors and diplomats reinterpreted models of public health and sanitary administration while creating institutions that challenged conventional concepts of borders, national policy, and state sovereignty. As a multinational event, the Conference marked the unprecedented transition from local, national and, bilateral public health policies into a coherent transnational project for the governance of epidemics. The dissertation is based on extensive research conducted in hitherto largely unexplored medical, diplomatic, and national collections in Britain, France, Italy, Portugal, Spain, and the United States of America. Sources ranging from diplomatic correspondence to medical publications and personal diaries, tie together multiple national and professional perspectives while untangling a diversity of personal and state agendas that fundamentally shaped the foundation of international public health mechanisms and contributed towards the crystallisation of medical concepts. Chapter one demonstrates how economic and political concerns about the impact of quarantine on international trade led to calls for international regulation and the standardization of quarantine practices in the Mediterranean region. Drawing on medical reports, pamphlets and diplomatic correspondence, the chapter exposes the multitude of quarantine practices in the Mediterranean region and a growing international demand for prophylactic reform. These exchanges, it is shown, culminated with the organization of the 1851 International Sanitary Conference in Paris. Chapter two argues that the Conference challenged previous diplomatic and medical protocols by including two professional groups in the process of regulating international public health. The lack of precedent allowed diplomatic and medical delegates to establish new rules for the conduct of the conference, which gave them a relatively high level of autonomy from the states they represented. Chapter three focuses on the problems of constructing a shared aetiological classification and regulating quarantine practices. It shows that, although doctors gained progressive control over the Conference, ultimately diplomatic agendas shaped the final outcome. In addition, it demonstrates that, rather than defending the elimination of quarantines, liberal states supported the continuation of quarantine practice in the Mediterranean; albeit that they managed to severely limit its operation in practice. Finally, chapter four examines how European and Oriental sanitary institutions were uniformly redesigned and new international judicial mechanisms created. These measures variously affected the sovereignty of the participating states by limiting their independent capacity to set national epidemic policies. However, the chapter argues that these negotiations took the shape of sovereignty bargains: by loosening control over specific elements of their sovereignty, states managed to advance their political, economic and sanitary agendas. By looking at the International Sanitary Conference of 1851, this dissertation shows how the foundations of international public health had consequences not only for the control of epidemic diseases and the circulation of goods and people in the Mediterranean region, but also for the authority and status of the nation states. By doing so, it reveals that international public health governance resulted from the amalgamation of a particular configuration of expert and diplomatic struggles and compromises. Moreover, the dissertation shifts the traditional local and national focus in the history of medicine to a wider and international context where local and national traditions struggled to produce coherent discourses and practices.