Historical Organization
League of Nations
League of Nations
Details
Organization Timeline
German South-West Africa surrenders to South African forces
📅 9 July 1915German forces surrendered after South African troops occupied the colony during a campaign aimed partly at denying Germany ports and wireless stations. The territory was later placed under South...
Allied leaders place former colonies under a new mandate system
📅 30 January 1919On 30 January, the Paris Peace Conference's Supreme Council agreed to allocate former German and Ottoman territories through a League of Nations mandate framework. The language of trusteeship and...
Treaty of Versailles transfers Germany’s colonies into mandates
📅 28 June 1919The Versailles settlement stripped Germany of its overseas colonies and placed them under League of Nations mandates administered by victorious powers. The arrangement was described as international...
Treaty of Versailles reshapes Europe while leaving colonial rule intact
📅 28 June 1919The treaty signed at Versailles on 28 June imposed territorial, military, and financial terms on Germany. It entered into force on 10 January 1920. Germany's overseas colonies were transferred into...
League of Nations begins work without Soviet Russia
📅 10 January 1920The League of Nations formally began operations. Soviet Russia was excluded from the postwar international order, while the new state denounced imperial arrangements and sought diplomatic recognition....
Treaty of Versailles enters into force and brings the League of Nations into being
📅 10 January 1920The treaty entered into force, bringing the League of Nations into being and creating an international body that addressed slavery and forced labor. The new order remained dominated by empires and did...
League of Nations begins work without the United States
📅 10 January 1920The League of Nations covenant entered into force, promising collective security and a mandate system. The League’s membership excluded major powers at different times, and its mandate structure...
San Remo conference assigns mandates over former Ottoman lands
📅 25 April 1920Allied powers assigned mandates over Iraq and Palestine to Britain and Syria and Lebanon to France. The League framework called mandates a form of tutelage, yet decisions were made without popular...
League of Nations approves the Mandate for Palestine
📅 24 July 1922The League Council approved Britain’s Mandate, incorporating the Balfour Declaration and assigning Britain responsibility for facilitating a Jewish national home. The document recognized the rights of...
Germany joins the League of Nations
📅 8 September 1926Germany entered the League of Nations with a permanent seat on its Council after Locarno and the Dawes reparation plan. Its admission marked a move from exclusion toward diplomatic reintegration,...
League of Nations adopts the Slavery Convention
📅 25 September 1926The convention committed states to suppress slavery and the slave trade and defined slavery in international law. Its adoption marked a major diplomatic recognition, but colonial forced labor and...
Japan invades Manchuria after the Mukden incident
📅 18 September 1931Japanese troops used an explosion on the South Manchuria Railway as a pretext to seize Mukden and occupy Manchuria. China appealed to the League of Nations, exposing the weakness of collective...
Japanese forces use the Mukden Incident to occupy Manchuria
📅 18 September 1931An explosion near the Japanese-owned South Manchurian Railway was used as a pretext for the Kwantung Army to seize cities across Manchuria. China appealed to the League of Nations, whose inquiry...
Japan proclaims the puppet state of Manchukuo
📅 1 March 1932Japan announced Manchukuo in occupied Manchuria, presenting a state under the nominal rule of former Qing emperor Puyi. The Lytton Commission later concluded that the new state did not represent a...
Iraq enters the League and the British mandate formally ends
📅 3 October 1932The League of Nations admitted Iraq as a member, formally ending Britain’s mandate. Independence followed years of revolt and negotiation, but British military rights, treaty obligations, and...
Japan gives notice of withdrawal from the League of Nations
📅 27 March 1933After the League rejected Japan’s claim to Manchuria, Tokyo notified the League that it would withdraw. The notice came two years after the invasion and signaled the limits of an institution unable or...
Japan gives notice of withdrawal from the League of Nations
📅 27 March 1933Japan formally notified the League of Nations that it would withdraw after the League rejected recognition of Manchukuo. The withdrawal followed Japan's occupation of Manchuria and the Lytton inquiry....
Soviet Union joins the League of Nations
📅 18 September 1934Admission marked a turn toward collective security diplomacy. Soviet participation challenged isolation but remained shaped by strategic calculation and the imperial structures of international order.
Italy invades Ethiopia
📅 3 October 1935Italy’s invasion of Ethiopia provoked condemnation and solidarity across Africa and the diaspora. The attack on one of the few African states then retaining sovereignty exposed the limits of the...
Italy invades Ethiopia, defying the League of Nations
📅 3 October 1935Italian forces crossed into Ethiopia from Eritrea and Italian Somaliland, beginning a war of conquest. Ethiopia, one of the League’s few African members, appealed for collective action, but...
Fascist Italy invades Ethiopia
📅 3 October 1935Italian forces invaded Ethiopia from Eritrea and Italian Somaliland, using superior weapons and chemical agents against a sovereign African state. Ethiopia appealed to the League of Nations, whose...
Haile Selassie appeals to the League as Ethiopia faces occupation
📅 30 June 1936Emperor Haile Selassie addressed the League of Nations after Italy’s invasion and occupation of much of Ethiopia. He warned that abandoning collective security would place every small state at risk....
League of Nations expels the Soviet Union
📅 14 December 1939The League condemned the Soviet invasion of Finland and expelled the USSR. The decision exposed the weakness of collective security and the limits of Soviet claims to defend peace through...