Start and end dates
List of timelines of World War II Timelines of World War II Chronological Prelude Events (in Asiain Europe) Aftermath 1939 1940 1941 1942 1943 1944 1945 Aftermath By topic Causes (Diplomacy) Declarations of war BattlesOperations By theatre Battle of Europe air operations Eastern FrontManhattan Project United Kingdom home front Surrender of the Axis armies vte Most historians agree that World War II began with the German invasion of Poland on 1 September 1939 and the British and French declarations of war on Germany two days later. Dates for the beginning of the Pacific War include the start of the Second Sino-Japanese War on 7 July 1937, or the earlier Japanese invasion of Manchuria on 18 September 1931. Other proposed starting dates include the Italian invasion of Abyssinia on 3 October 1935. The British historian Antony Beevor views the beginning of World War II as the Battles of Khalkhin Gol fought between Japan and the forces of Mongolia and the Soviet Union from May to September 1939. Others view the Spanish Civil War as the start or prelude to World War II. The date of the war's end is also not universally agreed upon. It was generally accepted at the time that the war ended with the armistice of 15 August 1945 (V-J Day), rather than with the formal surrender of Japan on 2 September 1945, which officially ended the war in Asia. A peace treaty between Japan and the Allies was signed in 1951. A 1990 treaty regarding Germany's future allowed the reunification of East and West Germany to take place. No formal peace treaty between Japan and the Soviet Union was ever signed, although the state of war between the two countries was terminated by the Soviet–Japanese Joint Declaration of 1956, which also restored full diplomatic relations between them.
Background
Causes of World War II Aftermath of World War I The League of Nations assembly, held in Geneva, Switzerland (1930) World War I had radically altered the political European map with the defeat of the Central Powers—including Austria-Hungary, Germany, Bulgaria and the Ottoman Empire—and the 1917 Bolshevik seizure of power in Russia, which led to the founding of the Soviet Union. Meanwhile, the victorious Allies of World War I, such as France, Belgium, Italy, Romania, and Greece, gained territory, and new nation-states were created out of the dissolution of the Austro-Hungarian, Ottoman, and Russian Empires.[failed verification] To prevent a future world war, the League of Nations was established in 1920 by the Paris Peace Conference. The organisation's primary goals were to prevent armed conflict through collective security, military, and naval disarmament, as well as settling international disputes through peaceful negotiations and arbitration. Despite strong pacifist sentiment after World War I, irredentist and revanchist nationalism had emerged in several European states. These sentiments were especially pronounced in Germany due to the significant territorial, colonial, and financial losses imposed by the Treaty of Versailles. Under the treaty, Germany lost around 13 percent of its home territory and all its overseas possessions, while German annexation of other states was prohibited, reparations were imposed, and limits were placed on the size and capability of the country's armed forces. Germany and Italy The German Empire was dissolved in the German revolution of 1918–1919, and a democratic government, later known as the Weimar Republic, was created. The interwar period saw strife between supporters of the new republic and hardline opponents on both the political right and left. Italy, as an Entente ally, had made some post-war territorial gains; however, Italian nationalists were angered that the promises made by the United Kingdom and France to sec
Pre-war events
Italian invasion of Ethiopia (1935) Second Italo-Ethiopian War Benito Mussolini inspecting troops during the Italo-Ethiopian War, 1935 The Second Italo-Ethiopian War was a colonial war that began in October 1935 and ended in May 1936. The war began with the invasion of the Ethiopian Empire (also known as Abyssinia) by the armed forces of the Kingdom of Italy (Regno d'Italia), which was launched from Italian Somaliland and Eritrea. The war resulted in the military occupation of Ethiopia and its annexation into the newly created colony of Italian East Africa (Africa Orientale Italiana); in addition it exposed the weakness of the League of Nations as a force to preserve peace. Both Italy and Ethiopia were member nations, but the League did little when the former clearly violated Article X of the League's Covenant. The United Kingdom and France supported imposing sanctions on Italy for the invasion, but the sanctions were not fully enforced and failed to end the Italian invasion. Italy subsequently dropped its objections to Germany's goal of absorbing Austria. Spanish Civil War (1936–1939) Spanish Civil War When civil war broke out in Spain, Hitler and Mussolini lent military support to the Nationalist rebels, led by General Francisco Franco. Italy supported the Nationalists to a greater extent than the Nazis: Mussolini sent more than 70,000 ground troops, 6,000 aviation personnel, and 720 aircraft to Spain. The Soviet Union supported the existing government of the Spanish Republic. More than 30,000 foreign volunteers, known as the International Brigades, also fought against the Nationalists. Both Germany and the Soviet Union used this proxy war as an opportunity to test in combat their most advanced weapons and tactics. The Nationalists won the civil war in April 1939; Franco, now dictator, remained officially neutral during World War II but generally favoured the Axis. His greatest collaboration with Germany was the sending of volunteers to fight on the
Course of the war
For a chronological guide, see List of timelines of World War II. Diplomatic history of World War II and World War II by country War breaks out in Europe (1939–1940) European theatre of World War II A German propaganda photograph reenacting the removal of the Polish border crossing in Sopot On 1 September 1939, Germany invaded Poland after having staged several false flag border incidents as a pretext to initiate the invasion. The first German attack of the war came against the Polish defences at Westerplatte. The United Kingdom responded with an ultimatum for Germany to cease military operations, and on 3 September, after the ultimatum was ignored, Britain and France declared war on Germany.[c] During the Phoney War period, the alliance provided no direct military support to Poland, outside of a cautious French probe into the Saarland. The Western Allies also began a naval blockade of Germany, which aimed to damage the country's economy and war effort. Germany responded by ordering U-boat warfare against Allied merchant and warships, which would later escalate into the Battle of the Atlantic. On 8 September, German troops reached the suburbs of Warsaw. The Polish counter-offensive to the west halted the German advance for several days, but it was outflanked and encircled by the Wehrmacht. Remnants of the Polish army broke through to besieged Warsaw. On 17 September 1939, two days after signing a cease-fire with Japan, the Soviet Union invaded Poland under the supposed pretext that the Polish state had ceased to exist. On 27 September, the Warsaw garrison surrendered to the Germans, and the last large operational unit of the Polish Army surrendered on 6 October. Despite the military defeat, Poland never surrendered; instead, it formed the Polish government-in-exile and a clandestine state apparatus remained in occupied Poland. A significant part of Polish military personnel evacuated to Romania and Latvia; many of them later fought against the Axis
Aftermath
Main articles: Aftermath of World War II and Consequences of Nazism Defendants at the Nuremberg trials, where the Allied forces prosecuted prominent members of the political, military, judicial, and economic leadership of Nazi Germany for crimes against humanity The Allies established occupation administrations in Austria and Germany, both initially divided between western and eastern occupation zones controlled by the Western Allies and the Soviet Union, respectively. However, their paths soon diverged. In Germany, the western and eastern occupation zones officially ended in 1949, with the respective zones becoming separate countries, West Germany and East Germany. In Austria, however, occupation continued until 1955, when a joint settlement between the Western Allies and the Soviet Union permitted the reunification of Austria as a democratic state officially non-aligned with any political bloc (although in practice having better relations with the Western Allies). A denazification program in Germany led to the prosecution of Nazi war criminals in the Nuremberg trials and the removal of ex-Nazis from power, although this policy moved towards amnesty and re-integration of ex-Nazis into West German society. Germany lost a quarter of its pre-war (1937) territory. Among the eastern territories, Silesia, Neumark and most of Pomerania were taken over by Poland, and East Prussia was divided between Poland and the Soviet Union, followed by the expulsion to Germany of the nine million Germans from these provinces, as well as three million Germans from the Sudetenland in Czechoslovakia. By the 1950s, one-fifth of West Germans were refugees from the east. The Soviet Union also took over the Polish provinces east of the Curzon Line, from which two million Poles were expelled. Northeastern Romania, parts of eastern Finland, and the Baltic states were annexed into the Soviet Union. Italy lost its monarchy, colonial empire, and some European territories. In an effort to
Impact
Historiography of World War II Casualties World War II casualties Bodies of Chinese civilians killed by the Imperial Japanese Army during the Nanjing Massacre in December 1937 An estimated 60 million to more than 75 million people died in the war including at least 20 million who died from deprivation, famine and disease. Civilian deaths have been estimated to comprise 67% to 80% of all direct and indirect deaths from the war. The Soviet Union had the highest overall death toll (estimated at 20 million to 28 million), followed by China (at least 15 million), Germany (6 million to 8.7 million) and Poland (5 million to 6.5 million). The countries which sustained the most military deaths were the Soviet Union (about 8.7 million), Germany (around 5.3 million), China (2 million to 3 million) and Japan (1.7 million to 2.5 million). Of the 20 million to 25 million military deaths in the war, the majority were of German and Soviet soldiers, including prisoners of war (POWs), on the Eastern Front. The high civilian death toll relative to military deaths was unusual for major wars up to that time. Some 10 million to 15 million people died of starvation and disease in China and the Soviet Union, and 8 million to 10 million in India and under Japanese occupation elsewhere in Asia and the Pacific. Around 15 million civilians died in genocides and other deliberate killings, while millions in total died in concentration camps, aerial bombings and in combat zones. Genocide, war crimes and crimes against humanity Prisoner identity photograph of a Polish girl taken by the German SS in Auschwitz. Approximately 230,000 children were held prisoner and used in forced labour and Nazi medical experiments. In trials following the war, representatives of the Axis powers and their accomplices were convicted of numerous war crimes, crimes against humanity and complicity in genocides. The Nazis killed about 6 million Jews in a racially motivated genocide known as the Holocaust. They also