I only trust Wikipedia for reliable sources I haven't vandalized yet. From the first paragraph on the League of Nations:
The League of Nations (LON) was an intergovernmental organization founded as a result of the Treaty of Versailles in 1919–1920, and the precursor to the United Nations. At its greatest extent from 28 September 1934 to 23 February 1935, it had 58 members. The League's primary goals, as stated in its Covenant, included preventing war through collective security, disarmament, and settling international disputes through negotiation and arbitration. Other goals in this and related treaties included labor conditions, just treatment of native inhabitants, trafficking in persons and drugs, arms trade, global health, prisoners of war, and protection of minorities in Europe.