Timeline of events preceding World War II

This Timeline of events preceding World War II covers the events of the interwar period (1918-1939) after World War I that effected or led to World War II.

1918
November 11
 * The Armistice with Germany marks the end of World War I. German troops evacuate occupied territories and Allied troops subsequently move in and occupy the German Rhineland.

1919
January 4-15
 * The Spartacist uprising takes place and is crushed by the German government, marking the end of the German Revolution.

January 18
 * Opening of the Paris Peace Conference to negotiate peace treaties between the belligerents of World War I.

February
 * The Polish–Soviet War begins with border clashes between the two states.

March 2
 * Foundation of the Third International, or Comintern in Moscow. Comintern's stated aim is to create a global Soviet republic.

May 15
 * The Turkish War of Independence begins as Greek troops land in Smyrna.

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. The United States signed the treaty but did not ratify it, later making a separate peace treaty with Germany.

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 German Austria has to change its name to Austria. The United States did not ratify the treaty and later makes a separate peace treaty with Austria.

November 27
 * Bulgaria signs the Treaty of Neuilly-sur-Seine. The peace treaty with the Allies regulates the borders of Bulgaria, the Bulgarian army is reduced to 20,000 men and Bulgaria is ordered to pay war reparations. Bulgaria and the United States did not declare war against each other, so no treaty was necessary.

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.

March
 * The failed Kapp Putsch takes place against the German government.

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
 * Turkey signs the Treaty of Sèvres with the Allied powers. 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. Turkey and the United States did not declare war against each other, so no treaty was necessary.

1921
March
 * The Polish–Soviet War ends with the Peace of Riga.

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.

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.

April 16
 * Germany and the Soviet Union sign the Treaty of Rapallo, re-establishing diplomatic relations, renouncing financial claims on each other and pledge future 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 29
 * Fascist leader Benito Mussolini is appointed prime minister of Italy by king Victor Emmanuel III after the March on Rome.

November 1
 * The Grand National Assembly of Turkey abolishes the Ottoman Sultanate.

1923
January 11
 * France occupies the Ruhr in an effort to compel Germany to step up its payments of war reparations.

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 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 leadership.

June 10
 * Italian Fascists kidnap and kill socialist leader Giacomo Matteotti in Rome.

1925
February 1
 * The Soviet Union recognizes the United Kingdom.

April 1
 * Adolf Hitler is sentenced to 5 years in jail for his participation in the Beer Hall Putsch (he serves only 9 months).

April 6
 * Fascists win elections in Italy with a 2/3 majority.

August 18
 * France begins withdrawing its troops from the Ruhr in Germany.

December 3
 * The Locarno Treaties are signed in London (they are ratified 14 September 1926). The treaties settle the borders of western Europe and normalizes relations between Germany and the Allied powers of western Europe.

1926
January 3
 * Theodoros Pangalos declares himself dictator of Greece.

January 31
 * British and Belgian troops leave Cologne, Germany.

April 4
 * Greek dictator Theodoros Pangalos is elected president.

April 24
 * The Treaty of Berlin is signed by Germany and the Soviet Union, which declares neutrality if either country is attacked within the next five years.

December 25
 * Emperor Taishō dies and his son Hirohito becomes the Emperor of Japan.

1927
April 12
 * The Chinese Civil War begins between nationalists and communists.

May 20
 * Saudi Arabia becomes independent from the United Kingdom.

June 7
 * Peter Voikov, Soviet ambassador to Warsaw, is assassinated by a White movement activist.

November 12
 * Leon Trotsky is expelled from the Soviet Communist Party, leaving Joseph Stalin with undisputed control of the Soviet Union.

1928

 * The Soviet Union launches the First Five-Year Plan, an economic effort to increase industrialization.

May 3
 * The Jinan Incident begins, a limited armed conflict between the Republic of China and Japan.

June 4
 * Huanggutun Incident: Japanese agents assassinate the Chinese warlord Zhang Zuolin.

August 2
 * Italy and Ethiopia sign the Italo-Ethiopian Treaty, pledging cooperation and friendship.

August 27
 * The Kellogg-Briand Pact is signed in Paris by the major powers of the world. The treaty outlaws aggressive warfare.

1929
February 9
 * Litvinov's Pact is signed in Moscow by the Soviet Union, Poland, Estonia, Romania and Latvia. The Pact outlaws aggressive warfare along the lines of the Kellog-Briand Pact.

February 11
 * Italy and Vatican City sign the Lateran Treaty, normalizing relations between the Vatican and Italy.

March 28
 * Japan withdraws troops from China, ending the Jinan Incident.

April 3
 * Persia signs Litvinov's Pact.

June 7
 * The Lateran Treaty is ratified, making the Vatican a sovereign state.

July 24
 * The Kellogg-Briand Pact goes into effect.

October 29
 * The Great Depression begins with the Wall Street Crash.

1930
April 22
 * The United Kingdom, United States, Italy and Japan sign the London Naval Treaty regulating submarine warfare and limiting naval shipbuilding.

June 30
 * France withdraws its remaining troops from the Rhineland ending the occupation of the Rhineland.

1931
September 18
 * Mukden Incident: the Japanese stage a false flag bombing against a Japanese-owned railroad in the Chinese region of Manchuria, blaming Chinese dissidents for the attack.

September 19
 * Using the Mukden Incident as a pretext, the Japanese invade Manchuria.

1932

 * The Soviet famine of 1932–33 begins, caused in part by the collectivization of agriculture of the First Five Year Plan.

January 7
 * The Stimson Doctrine is proclaimed by United States Secretary of State Henry L. Stimson in response to Japan invading Manchuria. The Doctrine holds that the United States government will not recognize border changes that are made by force.

January 28
 * January 28 Incident: using a flare-up of anti-Japanese violence as a pretext, the Japanese attack Shanghai, China. Fighting ends on March 6, and on May 5 a ceasefire agreement is signed wherein Shanghai is made a demilitarized zone.

February 27
 * Fighting between China and Japan in Manchuria ends with Japan in control of Manchuria.

March 1
 * Japan creates the puppet state Manchukuo out of occupied Manchuria.

April 10
 * Paul von Hindenburg is reelected President of Germany, defeating Adolf Hitler in a run-off.

May 30
 * Chancellor of Germany Heinrich Brüning resigns. President von Hindenburg asks Franz von Papen to form a new government.

August 30
 * Hermann Göring is elected chairman of the German Senate.

November 21
 * Paul von Hindenburg begins talking to Adolf Hitler about forming a new government.

December 3
 * von Hindenburg names Kurt von Schleicher Chancellor of Germany.

1933
January 1
 * Defense of the Great Wall: Japan attacks the fortified eastern end of the Great Wall of China in Rehe Province in Inner Mongolia.

January 30
 * Nazi leader Adolf Hitler is appointed Chancellor of Germany by President Paul von Hindenburg.

February 27
 * Germany's parliament building the Reichstag is set on fire.

February 28
 * The Reichstag Fire Decree is passed, nullifying many German civil liberties.

March 4
 * Franklin Delano Roosevelt is inaugurated as President of the United States.

March 20
 * Germany's first concentration camp, Dachau, is completed.

March 23
 * The Reichstag passes the Enabling Act, making Adolf Hitler dictator of Germany.

March 27
 * Japan leaves the League of Nations over the League of Nations' Lytton Report that found that Manchuria belongs to China and that Manchukuo was not a truly independent state.

April 26
 * The Gestapo secret police is established in Germany.

May 2
 * Hitler outlaws trade unions.

May 31
 * The Tanggu Truce is signed between China and Japan, setting the ceasefire conditions between the two states after the Japanese occupation of Manchuria. China accedes to all Japanese demands, creating a large demilitarized zone inside Chinese territory.

June 21
 * All non-Nazi parties are banned in Germany.

July 14
 * The Nazi party becomes the official party of Germany.

October 19
 * Germany leaves the League of Nations.

1934
January 26
 * Germany and Poland sign the 10 year German-Polish Non-Aggression Pact.

March 20
 * All German police forces come under the command of Heinrich Himmler.

June 30
 * Night of the Long Knives in Germany. Potential rivals to Hitler within the Nazi Party, including SA leader Ernst Röhm, and prominent anti-Nazi conservatives are killed by the SS and the Gestapo.

July 20
 * The SS becomes an organization independent of the Nazi Party, reporting directly to Adolf Hitler.

July 25
 * Austrian Nazis assassinate Engelbert Dollfuss during the failed July Putsch against the Austrian government.

August 2
 * Upon the death of President Paul von Hindenburg, Adolf Hitler makes himself Führer of Germany, becoming Head of State as well as Chancellor.

August 8
 * Members of the Wehrmacht begin swearing a personal oath of loyalty to Hitler instead of to the German constitution.

September
 * The Soviet Union joins the League of Nations.

December 5
 * The Abyssinia Crisis begins with the Walwal incident, an armed clash between Italian and Ethiopian troops on the border of Ethiopia.

December 29
 * Japan renounces the Washington Naval Treaty and the London Naval Treaty.

1935
January 7
 * The League of Nations approves the results of the Saar plebiscite, which allows Saar to be incorporated into German borders.

June 18
 * The Anglo-German Naval Agreement is signed by Germany and the United Kingdom. The agreement allows Germany to build a fleet that's 35% the size of the British fleet. In this way, the British hope to limit German naval re-armament.

October 2
 * Italy invades Ethiopia, beginning the Second Italo–Abyssinian War.

1936
In 1936, Adolf Hitler demanded to have a private meeting with Arnold J. Toynbee who was visiting Berlin the same year to address the Nazi Law Society, and Toynbee accepted. In the meeting, Hitler emphasized his limited expansionist aim of building a greater German nation, and his desire for British understanding and cooperation. Toynbee was convinced of Hitler's sincerity, and endorsed Hitler's message in a confidential memorandum for the British prime minister and foreign secretary.

March 7
 * In violation of the Treaty of Versailles, Germany remilitarizes the Rhineland.

May 5
 * Italian troops march into the Ethiopian capital, Addis Addeba, marking the end of the Second Italo–Abyssinian War.

July 17
 * The failed Spanish coup of July 1936 by Nationalist forces marks the beginning of the Spanish Civil War.

October 18
 * Hermann Göring is made head of the German Four Year Plan, an effort to make Germany self-sufficient and increase armaments.

October
 * The Great Purge commences in the Soviet Union with widespread repression of suspected opponents of the regime. The purge leads to the imprisonment and death of many military officers, weakening the Soviet Armed Forces ahead of World War II.

November 14
 * Suiyuan Campaign begins as Japanese-backed Mongolian troops attack the Chinese garrison at Hongort.

November 15
 * The aerial German Condor Legion goes into action for the first time.

November 25
 * The Anti-Comintern Pact is signed by Japan and Germany. The signing parties agree to go to war with the Soviet Union if one of the signatories is attacked by the Soviet Union.

December 1
 * Hitler makes it mandatory for all males between the ages 10-18 to join the Hitler Youth.

December 12
 * The two sides in the Chinese Civil War temporarily suspend hostilities to fight the Japanese.

December 23
 * The first 3,000 men of the Italian expeditionary force (later named Corpo Truppe Volontarie) lands in Cadiz in support of the Nationalist side in the Spanish Civil War.

1937
July 7
 * The Marco Polo Bridge Incident occurs, beginning the Second Sino-Japanese War.

November 6
 * Italy joins the Anti-Comintern Pact.

December 8
 * Japan established the puppet state of Mengjiang in the Inner Mongolia region of Republic of China.

December 11
 * Italy leaves the League of Nations.

1938
March 6
 * Japanese troops reaches the Yellow River in China.

March 13
 * Austria is annexed by Nazi Germany.

July 29
 * The Soviet–Japanese border conflicts begin with the Battle of Lake Khasan.

August
 * Soviet Union wins the Battle of Khasan against Japan.

September 30
 * The Munich Agreement is signed by Germany, France, the United Kingdom, and Italy. The agreement allows Germany to annex the Czechoslovak Sudetenland area in exchange for peace in an attempt to appease Hitler.

November 7
 * Exiled German Jew Herschel Grynszpan assassinates German consular aide Ernst vom Rath in Paris.

November 9
 * The Kristallnacht pogrom begins in Germany; Jewish shops and synagogues are smashed, looted, burned, and destroyed throughout the country.

1939
January 25
 * An uranium atom is split for the first time at Columbia University in the United States.

January 27
 * Adolf Hitler orders Plan Z, a 5-year naval expansion programme intended to provide for a huge German fleet capable of defeating the Royal Navy by 1944. The Kriegsmarine is given the first priority on the allotment of German economic resources. This is the first and only time the Kriegsmarine is given the first priority in the history of the Third Reich.

March 14
 * The pro-German Slovak Republic is created with Jozef Tiso as its first prime minister.

March 15
 * Germany occupies Czechoslovakia in violation of the Munich Pact. The Czechs do not attempt to put up any organized resistance having lost their main defensive line with the annexation of the Sudetenland.
 * Germany establishes the Protectorate of Bohemia and Moravia. The protectorate includes those portions of Czechoslovakia not incorporated into Germany, Poland, Hungary, or the new Slovak Republic.

March 20
 * German Foreign Minister Joachim von Ribbentrop delivers an oral ultimatum to Lithuania, demanding that it return the Klaipėda Region.

March 21
 * Adolf Hitler demands the return of the Free City of Danzig to Germany.

March 23
 * German–Romanian Treaty for the Development of Economic Relations between the Two Countries is signed.

March 31
 * The United Kingdom and France offer a guarantee of Polish independence.

April 1
 * The Spanish Civil War ends in Nationalist victory. Spain becomes a dictatorship with Francisco Franco as the head of the new government.

April 3
 * Adolf Hitler orders the German military to start planning for Fall Weiss, the codename for the attack on Poland, planned to be launched on August 25, 1939.

April 7-12
 * Italy invades Albania with little in the way of military resistance. Albania is later made part of Italy through a personal union of the Italian and Albanian crown.

April 18
 * The Soviet Union proposes a tripartite alliance with the United Kingdom and France. It is rejected.

April 28
 * In a speech before the Reichstag, Adolf Hitler renounces the Anglo-German Naval Agreement and the German–Polish Non-Aggression Pact

May 11
 * Soviet–Japanese border conflicts: Battle of Khalkhin Gol begins with Japan and Manchukuo against the Soviet Union and Mongolia. The battle ends in Soviet victory on September 16, influencing the Japanese to not seek further conflict with the Soviets, but to turn towards the Pacific holdings of the Euro-American powers instead.

May 17
 * Sweden, Norway, and Finland reject Germany's offer of non-aggression pacts.

May 22
 * The Pact of Steel, known formally as the "Pact of Friendship and Alliance between Germany and Italy", is signed by Fascist Italy and Nazi Germany. The Pact declares further cooperation between the two powers, but in a secret supplement the Pact is detailed as a military alliance.

June 14
 * The Tientsin Incident occurs, in which the Japanese blockade the British concession in the North China Treaty Port of Tientsin.

July 10
 * Prime Minister Neville Chamberlain reaffirms support for Poland and makes it clear that Britain did not view Free City of Danzig as being an internal German-Polish affair and would intervene on behalf of Poland if hostilities broke out between the two countries.

August 23
 * The Molotov-Ribbentrop Pact is signed between Nazi Germany and the Soviet Union, with secret provisions for the division of Eastern Europe - joint occupation of Poland and Soviet occupation of the Baltic States, Finland and Bessarabia. This protocol removes the threat of Soviet intervention during the German invasion of Poland.

August 25
 * In response to a message from Mussolini that Italy will not honor the Pact of Steel if Germany attacks Poland, Hitler delays the launch of the invasion by five days to provide more time to secure British and French neutrality.

September 1
 * Germany invades Poland, start of World War II.