Peace Treaty of Trianon with Hungary 1920 The Treaty of Trianon was a peace treaty between the Allied and Associated Powers and Hungary signed on June 4, 1920, at the Grand Trianon Palace at Versailles, France. The Treaty regulated the situation of the states that replaced the former Kingdom of Hungary, part of pre-war Austria-Hungary, after World War I. The winning parties of the Treaty included the "Allied Powers" (United States, Britain, France, Italy, and Japan) and the smaller "Associated Powers" (such as the main beneficiaries of the post-war territorial changes: Romania, the Kingdom of Serbs, Croats and Slovenes, and Czechoslovakia). The losing party was Hungary alone, since Austria-Hungary had by this time disintegrated. President Wilson followed by the American delegation and Lloyd George