Conventions or Treaties constituting International Courts and Tribunals (sensu stricto) are invariably multilateral as they are agreed upon to institute a permanent entity (similar domestic judicial bodies of the States´judiciary system) to settle eventual disputes under the rules of the constitutive instrument. Thus, multilateralism is an essential characteristic and permanent aspect of such instruments of International Law.
A bilateral agreement may be employed to create an ad hoc arbitral tribunal; however, under the conception sensu stricto of Court and Tribunal, State-State arbitration, both the permanent (as the Permanent Court of Arbitration) institution and the temporary one (ad hoc arbitration). Generally, such agreements are called arbitral (arbitration) agreement, compromise or compromis of arbitration. For instance, there was a dispute between Argentina and Chile concerning the territorial and maritime boundaries the title to certain islands, islets and rocks near the extreme end of the South American continent (the region of the eastern Beagle Channel). Then, an Arbitration Tribunal was established pursuant to a compromise signed on 22 July 1971. On 18 February 1977, the Tribunal rendered its award (which could not resolve the conflict because Argentina did accept its unfavourable result). Generally, a compromise of arbitration ensues from exchange of diplomatic notes.
The International Court of Justice, the International Tribunal for the Law of the Sea, and the International Criminal Court are illustrations of typical International Courts instituted by multilateral conventions with global reach. The African Court on Human Rights, the European Court of Human Rights, and the European Court of Justice are samples of International Courts in the regional sphere.