This doctoral thesis explores the key transnational institutions of European law academia and their role in the creation of a constitutional legal practice in the European Community from 1961 to 1993. Consisting of three case studies, it investigates the transnational federation gathering the national associations of European law: Fédération Internationale pour le Droit Européen, the European law journal Common Market Law Review, and the ITL project, carried out at the European University Institute.It carefully documents an alliance between academics and community actors with the aim of providing academic support to the constitutional claim, and it argues that the academic discipline of European law was built and developed through a circular attribution of legal ideas, legitimacy, and self-image between the European Court of Justice, the Commission, and academia –most particularly so at the transnational level.