Mixed arbitral tribunals, 1919–1930

The creation of a system of Mixed Arbitral Tribunals (MATs) was a major contribution of the post-WWI peace treaties to the development of international adjudication. Numerically speaking, the 36 MATs were undoubtedly the busiest international courts of the interwar period. Taken together, they decided on more than 70,000 cases, mostly covering private rights. The MATs are similarly remarkable from a procedural point of view. First, their respective rules of procedure were so detailed that contemporaries described them as 'miniature civil procedure codes'. Second, in a departure from most other international courts and tribunals, they also allowed individuals whose rights were at stake to become involved in the proceedings before them.