What international organization was established at the end of World War I?

The League of Nations was the international organization established at the end of World War I.

Its Covenant was included in the Treaty of Versailles, which was signed on 28 June 1919 during the Paris Peace Conference. The League formally came into existence on 10 January 1920, when the treaty took effect. Its main purpose was to prevent another large-scale war through collective security, negotiation, arbitration and arms reduction.

U.S. President Woodrow Wilson was one of the League’s strongest advocates and helped popularize the idea, although the United States never joined because the U.S. Senate rejected membership in the postwar treaties. The organization worked from Geneva and also addressed issues such as refugees, public health, labor conditions and human trafficking.

The League is often confused with the United Nations, but the United Nations was created after World War II in 1945. The League’s inability to stop aggression in the 1930s exposed serious weaknesses, and it was formally dissolved in 1946. Many of its institutions and responsibilities were then transferred to the UN.