The League of Nations (abbreviated LON in English, and SDN in its other official languages), was an intergovernmental organization founded as a result of the Paris Peace Conference that ended the First World War. It was the first permanent international organisation whose principal mission was to maintain world peace. Its primary goals, as stated in its Covenant, included preventing wars through collective security and disarmament, and settling international disputes through negotiation and arbitration. Other issues in this and related treaties included labour conditions, just treatment of native inhabitants, human and drug trafficking, arms trade, global health, prisoners of war, and protection of minorities in Europe. At its greatest extent from 28 September 1934 to 23 February 1935, it had 58 members. Many of which left towards the end.

The diplomatic philosophy behind the League represented a fundamental shift from the preceding hundred years. The League lacked its own armed force and depended on the Great Powers to enforce its resolutions, keep to its economic sanctions, or provide an army when needed. However, the Great Powers were often reluctant to do so. Sanctions could hurt League members, so they were reluctant to comply with them. When, during the Second Italo-Abyssinian War, the League accused Italian soldiers of targeting Red Cross medical tents, Benito Mussolini responded that "the League is very well when sparrows shout, but no good at all when eagles fall out."