<P> The League of Nations (abbreviated as LN in English, La Société des Nations (la sɔsjete de nɑsjɔ̃) abbreviated as SDN or SdN in French) was an intergovernmental organisation founded on 10 January 1920 as a result of the Paris Peace Conference that ended the First World War . It was the first 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, the 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 . </P> <P> 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 victorious Great Powers of WWI (France, the UK, Italy and Japan were the permanent members of the executive Council) to enforce its resolutions, keep to its economic sanctions, or provide an army when needed . The Great Powers were often reluctant to do so . Sanctions could hurt League members, so they were reluctant to comply with them . During the Second Italo - Abyssinian War, when 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 ." </P> <P> After some notable successes and some early failures in the 1920s, the League ultimately proved incapable of preventing aggression by the Axis powers in the 1930s . The credibility of the organization was somewhat weakened by the fact that United States never officially joined the League and the Soviet Union joined late and only briefly . Germany withdrew from the League, as did Japan, Italy, Spain, and others . The onset of the Second World War showed that the League had failed its primary purpose, which was to prevent any future world war . The League lasted for 26 years; the United Nations (UN) replaced it after the end of the Second World War and inherited several agencies and organisations founded by the League . </P> <P> The concept of a peaceful community of nations had been proposed as far back as 1795, when Immanuel Kant's Perpetual Peace: A Philosophical Sketch outlined the idea of a league of nations to control conflict and promote peace between states . Kant argued for the establishment of a peaceful world community, not in a sense of a global government, but in the hope that each state would declare itself a free state that respects its citizens and welcomes foreign visitors as fellow rational beings, thus promoting peaceful society worldwide . International co-operation to promote collective security originated in the Concert of Europe that developed after the Napoleonic Wars in the 19th century in an attempt to maintain the status quo between European states and so avoid war . This period also saw the development of international law, with the first Geneva Conventions establishing laws dealing with humanitarian relief during wartime, and the international Hague Conventions of 1899 and 1907 governing rules of war and the peaceful settlement of international disputes . As historians William H. Harbaugh and Ronald E. Powaski point out, Theodore Roosevelt was the first American President to call for an international league . At the acceptance for his Nobel Prize, Roosevelt said: "it would be a masterstroke if those great powers honestly bent on peace would form a League of Peace" </P>

When did the league of nations become the united nations