Mixed Arbitral Tribunals, 1919–1930:
An Experiment in the International Adjudication of Private Rights

Luxembourg, 30 September - 1 October 2021

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. This caseload is even more impressive if one considers that their existence generally did not exceed 10 years, as most of the MATs were discontinued pursuant to the 1930 Young Plan. 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. Although the MATs failed to produce a universally consistent body of case-law, their collection of published decisions was a major source for legal doctrine in the 1920s and 1930s and remains of interest for international lawyers today. The MATs themselves served as a source of inspiration for other international and supranational courts and tribunals, including the European Court of Justice. Their example might similarly inspire potential future negotiations over institutionalized investment tribunals.

And yet, like many other international 'experiments' of the interwar period, the MATs are often barely mentioned in post-WWII accounts of international law. Despite (or perhaps because of) the amount of cases they handled and the vastness of archival records they generated, they have not given rise to a single major monograph after 1945.

By organizing a conference specifically dedicated to the MATs and their impact on international adjudication of private rights, the Max Planck Institute Luxembourg for Procedural Law would like to shed new light on this often overlooked chapter in the history of international law.

THURSDAY, 30th September 2021

09:00 Welcome Address
Prof. Hélène Ruiz Fabri & Dr Michel Erpelding
09:15 Session 1:
A New Form of International Adjudication: The MATs in Context
Introductory Speaker and Chair: Dr. Jakob Zollman
  • Dr José Gustavo Prieto Muñoz: “Mexican Claims Commissions and Caudillos in the 20th Century: The Legitimacy for International Adjudication in Latin America”
  • Mr Willem Theus: “There and Back Again: From Consular Courts Through Mixed Arbitral Tribunals to International Commercial Courts”
  • Dr Zülâl Muslu: “The Mixed Arbitral Tribunals and Turkey: Negotiating the International Identity of the Young Republic Under the Sèvres Syndrome”
11:00Coffee break
11:30 Session 2:
Identifying the Claimants: The MATs and the Nationality of Private Persons
Chair: Prof. Hélène Ruiz Fabri
  • Dr Jakob Zollmann: “The Mixed Arbitral Tribunals and Citizenship. Histories of Nations, Autonomy and Anger, 1919 to 1930”
  • Mr Momchil L. Milanov : “Splitting the Atom of Nationality: The Mixed Arbitral Tribunal for Upper Silesia and the Emergence of Citizenship in International Law”
  • Prof. Emanuel Castellarin: “The Mixed Arbitral Tribunals and the Nationality of Legal Persons”
13:00 Lunch break
14:00 Session 3:
Arbitrators as Peacemakers: The Case of Prof. Paul Moriaud (1865-1924)
Chair: Prof. Valérie Rosoux
  • Dr Pascal Plas: “Paul Moriaud, la paix par l’abritrage. L’homme, les réseaux, les idées ” (FR)
  • Prof. Jacques Péricard: “Paul Moriaud et la mise en œuvre des Tribunaux arbitraux mixtes ” (FR)
  • Dr Michel Erpelding: “Paul Moriaud, the German–Belgian MAT, and the Case of the Belgian Deportees”

FRIDAY, 1st October 2021

09:00 Session 4:
Arbitral Awards as Sources of International Law: Assessing the Impact of the MATs’ Case-Law
Chair: Prof. Hélène Ruiz Fabri
  • Mr Guillaume Guez: “The Contribution of the MATs to the Law of Treaties”
  • Dr Mateusz Piątkowski: “The MATs and the Law of Air Warfare: The Tragic Impact of the Awards in Coenca Brothers and Kiriadolou”
  • Dr León Castellanos-Jankiewicz: ”Escaping the State: The Mixed Arbitral Tribunals and Private International Law”
10:30 Coffee break
11:00 Session 5:
The MATs and the Protection of Private Property: From the Interwar Period to Present-Day Debates on Investor-State Arbitration
Chair: Prof. Hans Van Houtte
  • Dr Marilena Papadaki : “The Romanian-Hungarian MAT: Protection of Enemy Private Property, Questions of Jurisdiction, and the Council of the League of Nations”
  • Prof. Maja Stanivuković & Dr Sanja Djajić: “Something Old, Something New: The 1930 Reform of the Trianon MATs and the Contemporary Discussion of the Appeal Mechanism in Investment Arbitration”
  • Dr Jarrod Hepburn: "Investment Treaty Arbitration and the Nascent Legacy of the MATs”
  • Dr Ewa Salkiewicz-Munnerlyn: "Interim Measures of Protection in the MAT's Jurisdiction"
13:00Concluding Remarks
Prof Burkhard Hess

Transnational Dispute Management (TDM, ISSN 1875-4120) is a comprehensive and innovative information service on the management of international disputes, with a focus on the rapidly evolving area of investment arbitration, but also in other significant areas of international investment (such as oil, gas, energy, infrastructure, mining, utilities etc).
It deals both with formal adjudicatory procedures (mainly investment and commercial arbitration), but also mediation/ADR methods, negotiation and managerial ways to manage transnational disputes efficiently. See www.transnational-dispute-management.com for more information. There you can apply for a free OGEMID trial membership and students can sign up for Young-OGEMID (which is free).

Max Planck Institute Luxembourg
Conference room, 4th floor
4, rue Alphonse Weicker
L-2721 Luxembourg

Poster: Download event poster here.