Drawing on the examples of the ICC and ICSID, this chapter shows how international arbitration has successively embraced a ‘relation-based’ and then a ‘rule-based’ model of governance. Initially, the systems of dispute resolution promoted by the ICC and ICSID displayed the features of the relation-based model. The ICC and ICSID sought to promote self-governance by pooling information concerning traders. A related goal was to encourage repeat business by creating an equitable method of dispute settlement that relied, to a large extent, on the participation of its users. The second step came, however, when self-governance failed to sustain cooperation, leading both the ICC and ICSID to promote a rule-based model of governance where third party-arbitrators and arbitral institutions gained increasing powers over the disputing parties. As a final step, arbitral tribunals evolved towards a fully judicialised system of dispute resolution, causing them to increasingly resemble national courts.