This timeline of events preceding World War II covers the events (mostly during the interwar period [1918–1939] after World War I) that affected or led to World War II.
1910s: 191019181919 1920s: 192019211922 1923192419251926 192719281929 1930s: 193019311932 1933193419351936 193719381939
Leaders of major participating countries
1895 October 8: Japanese agents assassinate Queen Min of Korea, removing a major obstacle to Japan's eventual conquest of Korea in the 1900s, ultimately facilitating Japan's invasion of Manchuria in 1931.
1905 September 5: The Treaty of Portsmouth formally ends the Russo-Japanese War, and concedes the Empire of Japan extraterritorial rights over the South Manchuria Railway Zone.
1910 August 22–29: Japan annexes Korea, further paving the way for the invasion of Manchuria in 1931.
1917 March 12 to November 7 [O.S. February 27 and October 25]: After years of strain brought about by war and food shortages, strikes broke out in the Russian capital of Saint Petersburg, while garrison troops refused to suppress the demonstrations. Facing the loss of support from the army and political elites, Tsar Nicholas II abdicated in March 1917, bringing an end to imperial rule in Russia. A Provisional Government was established, while authority was contested by the Petrograd Soviet in a period known as dual power. In November 1917 (October in the Julian calendar), members of the Bolshevik Party led by Vladimir Lenin seized power in Saint Petersburg, overthrowing the Provisional Government after its defenses collapsed with minimal resistance. The Bolshevik takeover marked the beginning of a broader struggle for control of the country, eventually leading to the Russian Civil War.
1918 October 28–31: The Aster Revolution occurs establishing the First Hungarian Republic. October 28: The German Revolution begins. It is sparked after the Imperial German Navy orders to send the High Seas Fleet to confront the British navy in a last stand attempt. Despite being planned that the mission would only be revealed when at sea, a rumor spreads that a combat mission is approaching and the sailors end up starting a mutiny as they feel it is a suicidal move. This mutiny ends up spreading to ports throughout the country. November 11: The Armistice with Germany marks the end of World War I. German troops are given 72 hours to evacuate occupied territories and Allied troops subsequently move in and occupy the German Rhineland. November 13: The Hungarian–Romanian War begins. December 27: Start of the Greater Poland Uprising against German rule.
1919 January 4–15: The Spartacist uprising takes place and is crushed by the German government. January 18: Opening of the Paris Peace Conference to negotiate peace treaties between the belligerents of World War I. January 31: Battle of George Square takes place in Glasgow: the British Army is called in by the city authorities to quell a riot during a strike for a 40 hour work week.
February: The Polish–Soviet War begins with border clashes between the two states. February 13: Japan issues the Racial Equality Proposal during the Paris Peace Conference. The proposal would abolish racial discrimination but it founders on opposition from the United States, Australia and New Zealand. March 2: Foundation of the Third International, or Comintern, in Moscow. Comintern's stated aim is to create a global Soviet republic. March 12: The Austrian Constituent National Assembly demands Austria's integration to Germany. March 21: Proclamation of the communist Hungarian Soviet Republic. May 15: The Turkish War of Independence begins as Greek troops land in Smyrna. June 21: A majority of the German fleet is scuttled at Scapa Flow in Scotland. The ships had been interned there under the terms of the 1918 Armistice while negotiations were occurring over the ships fate. The Germans feared that either the British would seize the ships or Germany would reject the Versailles Treaty and resume the war effort altogether with the ships likely being used against Germany in this case. June 28: Germany and the Allied powers sign the Treaty of Versailles after six months of negotiations. The German armed forces are limited in size to 100,000 personnel and Germany is ordered to pay large reparations for war damages. Germany's ships and submarines are confiscated, its territories in Oceania and China are stripped away, and Germany's army is banned from any planes, zeppelins, tanks, submarines, or large ships. The United States signed the treaty but did not ratify it, later making a separate peace treaty with Germany. July: An unknown corporal named Adolf Hitler infiltrates the German Workers' Party (the precursor of the Nazi Party) at the behest of the German Reichswehr. August 1: Fall of the short-lived Hungarian Soviet Republic. The Hungarian People's Republic is reestablished. August 3: The Hungarian–Romanian War ends. August 8: The Hungarian People's Republic is dissolved. September 10: German-Austria signs the Treaty of Saint-Germain. The peace treaty with the Allies regulates the borders of Austria, forbids union with Germany, and requires German-Austria to change its name to Austria. The United States did not ratify the treaty and later makes a separate peace treaty with Austria. September 12: Gabriele D'Annunzio leads a force of Italian nationalist irregulars in the seizure of the disputed city of Fiume (Rijeka). November 27: Bulgaria signs the Treaty of Neuilly-sur-Seine. The peace treaty gives Thrace back to Greece which was gained by them through the First Balkan War during 1913, while the Bulgarian army is reduced to 20,000 men and Bulgaria is ordered to pay war reparations.
1920 January 21: The Paris Peace Conference comes to an end with the inaugural General Assembly of the League of Nations. Although one of the victors of World War I, the United States never joins the League. February 24: The National Socialist German Workers' Party (better known as the Nazi Party) is founded in Munich.
March: The failed right-wing Kapp Putsch takes place against the German government. The German military remains passive and the putsch is defeated by a general strike. The German Ruhr Uprising, spurred by the general strike against the Kapp Putsch, is crushed by the German military. June 4: Hungary signs the Treaty of Trianon with the Allied powers. The treaty regulated the status of an independent Hungarian state and defined its borders. The United States did not ratify the treaty and later makes a separate peace treaty with Hungary.
August 10: The Ottoman Empire signs the Treaty of Sèvres with the Allied powers (except the US, which never declared war on Turkey). The treaty partitions the Ottoman Empire and the Turkish armed forces are reduced in size. Greece did not accept the borders as drawn up in the treaty and did not sign it. The Treaty of Sèvres was annulled in the course of the Turkish War of Independence and the parties signed and ratified the superseding Treaty of Lausanne in 1923. October: Żeligowski's Mutiny, a Polish force led by General Lucjan Żeligowski, capture Vilnius, officially without support from the Polish state. November 2: Franklin D. Roosevelt is defeated for the office of Vice President of the United States by Massachusetts Governor Calvin Coolidge. November 15: The Free City of Danzig is established in accordance with the Treaty of Versailles, as a contentious compromise between the generally nationalist German majority in the city, and Poland's right to free and secure access to the sea. December 24: Bloody Christmas: Italy occupies Fiume after five days of resistance from Gabriele D'Annunzio's legionnaires.
1921 Spring: Start of the Russian famine of 1921–1922 due to the combined effects of economic disturbance from the Russian Revolution, the Russian Civil War, and the government policy of war communism. March 7–17: Red Army mutineers and Russian civilians seize the strategic city of Kronstadt in the Kronstadt rebellion, demanding expanded civilian rights and an end to the Bolshevik monopoly on Soviet politics. After several days and several thousand casualties, the rebellion is crushed by Bolshevik forces from neighboring Petrograd.
March 18: The Polish–Soviet War ends with the Peace of Riga. April 24: The Fiuman electorate approves the idea of a Free State of Fiume. August 25: The U.S.–German Peace Treaty and the U.S.–Austrian Peace Treaty are signed, marking the formal end of the state of war between the two states and the United States instead of the Treaty of Versailles and the Treaty of Saint-Germain that were not ratified by the United States. August 29: The U.S.–Hungarian Peace Treaty is signed, marking the formal end of the state of war between the two states instead of the Treaty of Trianon that was not ratified by the United States. October 5: Foundation of the Sturmabteilung (SA), the paramilitary wing of the German Nazi Party. November 9: Foundation of the Italian National Fascist Party by Benito Mussolini during the Third Fascist Congress in Rome.
1922 February 6: The Washington Naval Conference ends with the signing of the Washington Naval Treaty by the United Kingdom, the United States, Japan, France, and Italy. The signing parties agree to limit the size of their naval forces. March: The first German officers travel to the Soviet Union for the purposes of military cooperation between Germany and the Soviet Union. April 16: Germany and the Soviet Union sign the Treaty of Rapallo, re-establishing diplomatic relations, renouncing financial claims on each other, and pledging future economic cooperation. October: The Russian Civil War (ongoing since 7 November 1917) ends in Bolshevik victory with the defeat of the last White forces in Siberia. October 11: Armistice of Mudanya is signed in the Turkish War of Independence. October 29: Fascist leader Benito Mussolini is appointed prime minister of Italy by king Victor Emmanuel III following the March on Rome. November 1: The Grand National Assembly of Turkey abolishes the Ottoman Sultanate.
1923
January 11: France and Belgium occupy the Ruhr in an effort to compel Germany to step up its payments of war reparations. January 26: The Nationalist Kuomintang party and the Chinese Communist Party form the First United Front to end warlordism in China. June: In the Great Inflation of 1923, the value of the German mark is destroyed. July 24: The Treaty of Lausanne, settling the boundaries of modern Turkey, is signed in Switzerland by Turkey and the Entente powers. It marks the end of the Turkish War of Independence and replaces the earlier Treaty of Sèvres August 31: The Corfu incident: Italy bombards and occupies the Greek island of Corfu seeking to pressure Greece to pay reparations for the murder of an Italian general in Greece. September 27: The Corfu incident ends; Italian troops withdraw after the Conference of Ambassadors rules in favor of Italian demands of reparations from Greece. October 23–25: The Hamburg Uprising occurs. October 29: Turkey officially becomes a Republic following the dissolution of the Ottoman Empire. November 8: The Beer Hall Putsch takes place, in which Adolf Hitler unsuccessfully leads the Nazis in an attempt to overthrow the German government. It is crushed by police the next day.
1924
January 21: Leader of the Soviet Union Vladimir Lenin dies, and Joseph Stalin begins purging rivals to clear the way for his dictatorship. February 1: The United Kingdom extends diplomatic recognition to the Soviet Union. March 16: Italy annexes the Free State of Fiume. April 1: Adolf Hitler is sentenced to 5 years in prison for his participation in the Beer Hall Putsch (he serves only 8 months). April 6: Fascists win the 1924 Italian general election with a 2/3 majority. June 10: Italian Fascists kidnap and kill socialist leader Giacomo Matteotti in Rome.