This is a timeline of formal declarations of War during World War II .
A declaration of war is a formal act by which one nation goes to war against another. The declaration is usually an act of delivering a performative speech (not to be confused with a mere speech) or the presentation of a signed document by an authorized party of a national government in order to create a state of war between two or more sovereign states. The official international protocol for declaring war was defined in The Hague Peace Conference of 1907 (or Hague II).For the diplomatic maneuvering behind these events, which led to hostilities between nations during World War II, see the article entitled Diplomatic history of World War II.
Below is a table showing the outbreak of wars between nations which occurred during World War II. Indicated are the dates (during the immediate build-up to, or during the course of, World War II), from which a de facto state of war existed between nations. The table shows both the "Initiator Nation(s)" and the nation at which the aggression was aimed, or "Targeted Nation(s)". Events listed include those in which there were simple diplomatic breaking of relations that did not involve any physical attack, as well as those involving overt declarations or acts of aggression. In rare cases, war between two nations occurred twice, with an intermittent period of peace. The list here does not include peace treaties or periods of any armistice.
Table Legend: Concerning Declaration of War: A = Attack without prior, formal declaration of war; U = State of war arrived at through use of ultimatum;
W = Formal declaration of war made.
|Date||Initiator nation(s)||Targeted nation(s)||Declaration of war: Type||Notes/comments||Document/event|
|1939-09-01||U||German attack began at 4:44 a.m., Berlin and Warsaw time.||Invasion|
|1939-09-03||U||At 11:15 a.m. London time, British PM, Neville Chamberlain publicly delivered his Ultimatum Speech.||Declaration|
|1939-11-30||A||Second war between these nations (after Finnish invasion in 1918-1920).||Invasion|
|1940-04-09||A|| Invasion of Denmark |
Invasion of Norway
|1940-05-10||A/W||Date of the German offensive in the West, W from Belgium and the Netherlands.|
|1940-06-10||W||France and the UK|
|1940-06-25||A||Vichy France cuts off diplomatic relations with the United Kingdom on 8 July 1940.||Attack|
|1940-09-09||A||Egypt maintained neutrality until 1945.||Invasion|
|1940-10-28||U||Italy invades Greece||Invasion|
|1941-04-14||A||Egypt maintained neutrality until 1945.||Invasion|
|1941-06-22||A||A timed-declaration of war was given by Germany at the time of the attack||Invasion|
|W||Tuva was a client state of the Soviet Union. Part of the USSR from 1944.|
|1941-06-25||W||Finland recognized a state of war with the Soviet Union; third war between these nations.||Continuation War|
|1941-12-07||A||W (Japanese point of view); A (British Empire and United States)|
|1941-12-08||W|| United States declaration |
|1941-12-08||W||South African declaration|
|1941-12-08||W||China and Japan had been at war since 1937||Second Sino-Japanese war|
|1941-12-08||W[ citation needed ]|
|1941-12-11||W||Japan rejected declaration of War. Prime Minister Hideki Tōjō's answer was following: "We don't accept the Polish declaration of war. The Poles, fighting for their freedom, declared war under the British pressure".|
|1941-12-12||A||Portugal maintained neutrality throughout World War II.|
|1942-01-01||United Nations||Axis Powers||W||Declared during Arcadia Conference||Declaration|
|1942-02-19||A||Portugal maintained neutrality throughout World War II.||Invasion|
|1942-12-14||W||On 3 October 1935, Italy invaded Ethiopia without a formal declaration of war. In response to the Italian invasion, Ethiopia declared war on Italy. Most of Ethiopia was occupied by Italy in 1936, however parts of Ethiopia remained under the control of the Ethiopian Patriots Movement, which begun its guerrilla war against the occupying Italian forces the day Addis Ababa fell in May 1936. In May 1941, Addis Ababa was liberated by the Gideon Force, restoring sovereignty to Ethiopia.||Second Italo-Ethiopian War|
|1943-01-20||Axis powers||W||President Juan Antonio Ríos officially broke Chile's neutrality and suspended all trade and diplomatic relations with the Axis powers, and Chile officially joined the Allies. Authorities began rooting out German spies from the Nazi-led Operation Bolivar. Foreigners suspected of spying for the Axis were sent to the Pisagua internment camp. While Chile would officially declare war on Japan in 1945, the American government and international press celebrated this day as Chile declaring war on the Axis.||Declaration|
|1943-04-02||Axis powers||W||Bolivia officially joined the Allies on 7 April 1943. Shortly after war was declared, the President Enrique Peñaranda, was overthrown in a coup. Bolivian mines supplied needed tin to the Allies, but no troops or warplanes were sent overseas. Bolivians remained confident their geographic isolation would protect them from the war.||Declaration|
|1943-10-13||W||Italy had changed sides after the fall of Mussolini. The Declaration of War was given by Pietro Badoglio to the German ambassador in Madrid.||Declaration|
|1943-11-26||W||See Colombia during World War II||Declaration|
|1944-08-25||W||Romania switched sides||Declaration|
|1944-09-08||W||Bulgaria switched sides||Declaration|
|1944-12-31||W||Hungary switched sides||Declaration|
|1945-03-03||W||Finland switched sides||Lapland War|
|1945-08-08||W||Last outbreak of war during the entire Second World War.||Declaration|
|1945-08-10||W||W (de jure) A (de facto 1945-08-09) War declared 24 hours after crossing the border with Soviet troops|
Ulrich Friedrich Wilhelm Joachim von Ribbentrop, better known as simply Joachim von Ribbentrop, was Foreign Minister of Nazi Germany from 1938 until 1945.
The Axis powers, also known as "Rome–Berlin–Tokyo Axis", were the nations that fought in World War II against the Allies. The Axis powers agreed on their opposition to the Allies, but did not completely coordinate their activity.
The Locarno Treaties were seven agreements negotiated at Locarno, Switzerland, on 5–16 October 1925 and formally signed in London on 1 December, in which the First World War Western European Allied powers and the new states of Central and Eastern Europe sought to secure the post-war territorial settlement, and return normalizing relations with defeated Germany. It also stated that Germany would never go to war with the other countries. Locarno divided borders in Europe into two categories: western, which were guaranteed by Locarno treaties, and eastern borders of Germany with Poland, which were open for revision.
The invasion of Poland, marked the beginning of World War II. The German invasion began on 1 September 1939, one week after the signing of the Molotov–Ribbentrop Pact between Germany and the Soviet Union. The Soviets invaded Poland on 17 September. The campaign ended on 6 October with Germany and the Soviet Union dividing and annexing the whole of Poland under the terms of the German–Soviet Frontier Treaty.
The Polish government-in-exile, officially known as the Government of the Republic of Poland in exile, was the government in exile of Poland formed in the aftermath of the Invasion of Poland of September 1939, and the subsequent occupation of Poland by Germany and the Soviet Union, which brought to an end the Second Polish Republic.
Historians from many countries gave deep attention to the causes of World War II. Leading themes include the political takeover in 1933 of Germany by Adolf Hitler and the Nazi Party, which ruthlessly promoted an aggressive foreign policy in violation of the Versailles Treaty of 1919, Japanese militarism against China, Italian aggression against Ethiopia, and the success of Germany in forming an agreement with the Soviet Union in August 1939 to divide up Eastern Europe. The immediate precipitating event was Germany invading Poland on September 1, 1939, and Britain and France declaring war on Germany on September 3, 1939.
Józef Beck was a Polish statesman who served the Second Republic of Poland as a diplomat and military officer, and was a close associate of Józef Piłsudski. Beck is most famous for being Polish foreign minister in the 1930s, when he largely set Polish foreign policy.
This timeline of events preceding World War II covers the events of the interwar period (1918–1939) after World War I that affected or led to World War II.
The Allies of World War II, called the United Nations from the 1 January 1942 declaration, were the countries that together opposed the Axis powers during the Second World War (1939–1945). The Allies promoted the alliance as a means to control German, Japanese and Italian aggression.
The German–Polish Non-Aggression Pact was an international treaty between Nazi Germany and the Second Polish Republic that was signed on January 26, 1934. Both countries pledged to resolve their problems by bilateral negotiations and to forgo armed conflict for a period of 10 years. The pact effectively normalised relations between Poland and Germany, which had been strained by border disputes arising from the territorial settlement in the Treaty of Versailles. Germany effectively recognised Poland's borders and moved to end an economically-damaging customs war between the two countries that had taken place over the previous decade.
The military alliance between the United Kingdom and Poland was formalised by the Anglo-Polish Agreement in 1939, with subsequent addenda of 1940 and 1944, for mutual assistance in case of a military invasion from Germany, as specified in a secret protocol.
The Polish–Romanian Alliance was a series of treaties signed in the interwar period by the Second Polish Republic and the Kingdom of Romania. The first of them was signed in 1921 and, together, the treaties formed a basis for good foreign relations between the two countries that lasted until World War II began in 1939.
The Soviet invasion of Poland was a military operation by the Soviet Union without a formal declaration of war. On 17 September 1939, the Soviet Union invaded Poland from the east, sixteen days after Germany invaded Poland from the west. Subsequent military operations lasted for the following 20 days and ended on 6 October 1939 with the two-way division and annexation of the entire territory of the Second Polish Republic by Nazi Germany and the Soviet Union. This division is sometimes called the Fourth Partition of Poland. The Soviet invasion of Poland was indirectly indicated in the "secret additional protocol" of the Molotov–Ribbentrop Pact signed on 23 August 1939, which approximately divided Poland into "spheres of influence" of the two powers and questioned the future existence of the Polish state.
This is a timeline of events that stretched over the period of World War II. For events preceding September 1, 1939, see the timeline of events preceding World War II.
The Molotov–Ribbentrop Pact was an August 23, 1939, agreement between the Soviet Union and Nazi Germany colloquially named after Soviet foreign minister Vyacheslav Molotov and German foreign minister Joachim von Ribbentrop. The treaty renounced warfare between the two countries. In addition to stipulations of non-aggression, the treaty included a secret protocol dividing several eastern European countries between the parties.
The timeline of the Molotov–Ribbentrop Pact is a chronology of events, including Molotov–Ribbentrop Pact negotiations, leading up to, culminating in, and resulting from the Molotov–Ribbentrop Pact. The Treaty of Non-aggression between Nazi Germany and the Soviet Union was signed in the early hours of August 24, 1939, but was dated August 23.
The diplomatic history of World War II includes the major foreign policies and interactions inside the opposing coalitions, the Allies of World War II and the Axis powers. The military history of the war is covered at World War II. The prewar diplomacy is covered in Causes of World War II and International relations (1919–1939).
The Declaration of war by France and the United Kingdom was given on 3 September 1939, after German forces invaded Poland. Despite the speech being the official announcement of both France and the United Kingdom, the speech was given by the British Prime Minister Neville Chamberlain, in Westminster, London.
The following events occurred in September 1939:
This is a timeline of formal declarations of War during World War I.