The ILO Constitution was written between January and April 1919 by the Commission on International Labour constituted by the Treaty of Versailles. The Commission was composed of representatives from nine countries (Belgium, Cuba, Czechoslovakia, France, Italy, Japan, Poland, the United Kingdom and the United States), under the chairmanship of Samuel Gompers, Head of the American Federation of Labour (AFL). It resulted in a tripartite organization, the only one of its kind bringing together representatives of governments, employers and workers in its executive bodies. The ILO Constitution became Part XIII of the Treaty of Versailles. The Preamble of the ILO Constitution opens with the affirmation that "universal and lasting peace can be established only if it is based on social justice". These ideals were further clarified in the Declaration of Philadelphia (1944). See: Declaration of Philadelphia