Defence date: 26 November 2012 Examining Board: Professor Fabrizio Cafaggi (EUI Supervisor) Professor Francesco Francioni (EUI) Professor Sandrine Clavel Université de Versailles-Saint Quentin Professor Fabrizio Marrella Università Cà Foscari di Venezia. First made available online: 2 August 2016 This dissertation suggests a new theory of lex mercatoria that takes into account the complex and spontaneous order of international commerce. Since the emphasis is put on the nature of this order, the concept of lex mercatoria is examined as an ex post governance mechanism resolving contractual disputes with a view to maintaining and restoring the order of internationa...