Allies of World War II

The Allies, or Allied powers, were formally called the United Nations from 1942. They were an international military coalition formed during World War II (1939–1945) to oppose the Axis powers. Their main members were the "Big Four": the United Kingdom, the Soviet Union, the United States, and China.

The Allies' membership changed during the war. When the conflict broke out on 1 September 1939, the coalition was made up of the United Kingdom, France, and Poland, along with their dependencies, such as British India. The independent dominions of the British Commonwealth, namely Canada, Australia, New Zealand, and South Africa, also joined them. For this reason, the early alliance was similar to that of the First World War. As Axis forces began invading northern Europe and the Balkans, the Allies added the Netherlands, Belgium, Norway, Greece, and Yugoslavia. The Soviet Union had first signed a non-aggression pact with Germany, which led to the Soviet invasion of Poland. It joined the Allies after the German invasion of the Soviet Union in June 1941. The United States had given some material support to European Allies since September 1940, but it stayed formally neutral until the Japanese attack on Pearl Harbor in December 1941. After that attack, it declared war and officially joined the Allies. The Republic of China had already been at war with Japan since 1937, after the Marco Polo Bridge incident, and formally joined the Allies in December 1941.

The "Big Three", which were the United Kingdom, the Soviet Union, and the United States, were the main sources of people, resources, and strategy, and each played a key role in winning the war. Relations between the United Kingdom and the United States were especially close, and their shared Atlantic Charter formed the basis of their alliance. A series of conferences among Allied leaders, diplomats, and military officials gradually shaped the alliance, the direction of the war, and the international order that followed.

The Allies became a formal group with the Declaration by United Nations on 1 January 1942, which 26 countries around the world signed. These countries ranged from governments in exile that had fled Axis occupation to small states far from the war. The Declaration officially recognized the Big Three and China as the "Four Powers", because they played a central role in fighting the war. They were also called the "trusteeship of the powerful" and later the "Four Policemen" of the United Nations. Many more countries joined before the war ended, including colonies and former Axis states.

After the war ended, the Allies and the Declaration that united them became the basis of the modern United Nations.

Main article: Causes of World War II

Origins

After the First World War, the Treaty of Versailles (1919) set up the League of Nations to keep peace by having countries protect each other. Four big allies from the First World War, the United Kingdom, France, Italy and Japan, became permanent members of the league's council. The league was weakened, though, because the United States did not join. France made its own agreements for protection, including the Franco-Polish alliance (1921) and a Franco-Czechoslovak alliance (1924). Under the Locarno treaties (1925), several countries promised to respect the borders set by the Treaty of Versailles. Japan left the league in February 1933 after the league criticised its invasion of Manchuria in 1931. Nazi Germany also left the league and the world disarmament conference in October 1933. In May 1935, France signed a mutual defence agreement with the Soviet Union, which Germany saw as aimed against it. Later that year, Italy invaded Abyssinia, and the league responded with weak, short-lived sanctions.

Germany remilitarised the Rhineland in March 1936, breaking the Versailles and Locarno treaties, but no sanctions were imposed. In July 1937, Japan began an undeclared war in China, and the league said Japan's actions were illegal. In November, Italy joined the German and Japanese Anti-Comintern pact. In March 1938, Germany invaded and annexed Austria. Britain continued its policy of appeasing Germany, pressing Czechoslovakia to accept a solution that Hitler would find acceptable, even though Germany had made threats over the Sudetenland region. On 30 September 1938, Britain, France, Germany, and Italy signed the Munich Agreement, which handed the Sudetenland to Germany and promised to protect the rump Czechoslovak state. Germany invaded Czechoslovakia on 15 March 1939, breaking that agreement. Germany then pressed Poland to hand over Danzig and the Polish corridor. In May, Germany and Italy signed the Pact of Steel. On 23 August, Germany and the Soviet Union signed a non-aggression pact, and two days later Britain signed a military alliance with Poland.

Further information: Diplomatic history of World War II

Grand Alliance

On 1 September 1939, Germany invaded Poland, and on 3 September, Britain and France declared war on Germany. The Soviet Union invaded Poland from the east but stayed officially neutral. In April 1940, Germany invaded western Europe, and Britain recognized Charles de Gaulle as leader of the Free-French forces in London, which opposed the collaborationist French Vichy government. At the First Inter-Allied Meeting in June 1941, the allies, including the British Dominions, produced the Declaration of St James's Palace. After Hitler broke his non-aggression agreement with Stalin and invaded the Soviet Union, Britain made an alliance with the Soviet Union. In August 1941, the Atlantic Conference between Franklin Roosevelt and Winston Churchill set out a shared vision for the post-war world, formalized as the Atlantic Charter. When Japan attacked American and British territories in December 1941, the United States entered the war as an Allied power. China had already been resisting Japan and declared war on the Axis. Churchill called the group the "Grand Alliance." The "Big Three" were the United Kingdom, the United States and the Soviet Union. On 1 January 1942, the Declaration by United Nations was signed by 26 countries, including United States, United Kingdom, Soviet Union, China, Australia, Belgium, Canada, Costa Rica, Cuba, Czechoslovakia, Dominican Republic, El Salvador, Greece, Guatemala, Haiti, Honduras, British India, Luxembourg, Netherlands, New Zealand, Nicaragua, Norway, Panama, Poland, South Africa and Yugoslavia. Later, the allies prepared for the San Francisco Conference to create the new United Nations organization.

Churchill and Roosevelt met often to shape the war and the post-war world, in a series of conferences. They attended the First Washington Conference and later met at Casablanca. At the Quebec Conference, they agreed on a new command structure in South-East Asia. At the Cairo Declaration meeting, they set out plans for post-war Asia. At the Tehran Conference, Churchill, Roosevelt and Stalin decided that an invasion of France was the priority. At the Yalta Conference, they discussed the post-war settlement of Europe. After victory in Europe, Harry S. Truman and Clement Attlee joined the final summit at Potsdam. The Allies also cooperated in other ways. Britain and the United States worked together through the destroyers-for-bases deal and Lend-Lease aid, which was also supplied through the British Commonwealth, the empire and the British Commonwealth. They also created a Combined Chiefs of Staff. Tensions remained. The two countries disagreed about when to invade France and how to fight Japan, including the Burma road. Stalin wanted an earlier invasion of France, and the Soviet Union also disagreed with its allies over the borders of postwar Europe. The Big Three alliance held until the end of the war. The Soviet Union also signed the Anglo-Soviet Treaty and the Four Powers Declaration. Stalin agreed to dissolve the Comintern. Relations with China were also difficult. Chinese leader Chiang Kai-shek and American officer Joseph Stilwell disagreed, and Chiang's standing weakened after Japan's China offensive of 1944.

Major Allied states

See also: Diplomatic history of World War II

Further information: Military history of the United Kingdom during World War II and British Empire in World War II

Main article: France during World War II

Further information: Liberation of France and Military history of France during World War II

Main article: French colonial empire

Further information: Military history of the Soviet Union during World War II

Further information: Military history of the United States during World War II

Main article: Second Sino-Japanese War

Main article: Nationalist Government

Main article: Communist-controlled China (1927–1949)

At the start of the war, the British Empire included over 60 countries, including the dominions, India, and many colonies. Britain declared war on Germany on 3 September 1939, and most of the empire was automatically at war with it. Australia, Canada, New Zealand, and South Africa then declared war themselves within the next two weeks. After Poland and France were defeated, the UK led the coordination of the empire's war effort. France declared war on Germany on 3 September 1939, and later its Free French forces continued the fight alongside the Allies. The Soviet Union had signed a pact with Germany in 1939 and then joined the Allies after Germany attacked it in June 1941.

The United States first supported Britain indirectly through the Lend-Lease program while it was still officially neutral. After the attack on Pearl Harbor in December 1941, the United States declared war on Japan, and Germany and Italy then declared war on the United States. China had been fighting Japan since 1937, but it only officially joined the Allies after Pearl Harbor. China was divided between the Nationalists, led by Chiang Kai-shek, and the Communists, led by Mao Zedong, until Japan surrendered in 1945.

Other Allied states

Further information: Military history of Australia during World War II

Main article: Belgium in World War II

Main article: Belgian colonial empire

Main article: Brazil in World War II

Main articles: Declaration of war by Canada § Germany, and Military history of Canada during World War II

Main article: Cuba during World War II

Further information: German occupation of Czechoslovakia and Czechoslovak government-in-exile

Further information: Military history of Greece during World War II, Axis occupation of Greece, and Greek Resistance

Main article: Luxembourg in World War II

See also: Luxembourgish government in exile, Luxembourg Resistance, Battle of the Bulge, and Luxembourg American Cemetery and Memorial

Main article: Mexico during World War II

Main article: Netherlands in World War II

Main article: Dutch Empire

Further information: Military history of New Zealand during World War II

Further information: German occupation of Norway

Further information: Polish contribution to World War II, Polish resistance movement in World War II, Polish Armed Forces in the West, and Polish Armed Forces in the East

Further information: Military history of South Africa during World War II

Main article: World War II in Yugoslavia

Main article: Yugoslav Partisans

Main article: Chetniks

Many other countries joined the Allies, each in its own way. Australia was a sovereign Dominion under the Australian monarchy and at first followed Britain's foreign policy, declaring war on Germany on 3 September 1939. Belgium had pursued neutrality before being invaded by Germany on 10 May 1940, and then fought alongside French and British forces. Its government went into exile in London, and Belgian troops kept fighting as the Free Belgian Forces. Brazil first stayed neutral, but after 36 of its merchant ships were sunk, it declared war on Germany and Italy on 22 August 1942 and later sent an Expeditionary Force to fight on the Italian front. Canada, a sovereign Dominion under the Canadian monarchy, was the last member of the Commonwealth to declare war on Germany, on 10 September 1939. Cuba declared war on the Axis powers in December 1941 and became one of the greatest beneficiaries of the United States' Lend-Lease program. The Dominican Republic offered to accept up to 100,000 Jewish refugees at the Évian Conference and declared war on 11 December 1941. Czechoslovakia's Czechoslovak government-in-exile declared war on the Axis powers in December 1941. Egypt remained formally neutral for a long time and declared war on Germany and Japan on 26 February 1945. Ethiopia's Emperor Haile Selassie I returned to his rule on 18 January 1941, and Ethiopia declared war on Germany, Italy and Japan in December 1942.

Other countries also took part. Greece was invaded by Italy in 1940 and joined the Allies, but German forces later occupied most of the country, and a strong resistance movement grew there. Luxembourg, like Belgium, became an Allied member after being invaded by Germany on 10 May 1940, and its government in exile broadcast to the occupied country on BBC Radio. Mexico declared war on Germany in 1942 after German submarines attacked its oil tankers, and its Escuadrón 201 fighter squadron helped in the liberation of Luzon in 1945. The Netherlands was defeated and occupied by Germany, and it was liberated by Canadian, British, American and other Allied forces in 1944 and 1945. New Zealand declared war on Germany on 3 September 1939, just hours after Britain, as a sign of loyalty to Britain. Norway was invaded by Germany in April 1940, and its forces in exile later operated under British command. Poland's Invasion of Poland started the war in Europe, and its Home Army provided intelligence to the Allies. Saudi Arabia supplied the Allies with large amounts of oil and declared war on Germany and Japan in 1945. South Africa's entry into the war was politically divided, but Jan Smuts led the country into war on the Allied side. Yugoslavia entered the war on the Allied side, was quickly defeated after the invasion of Axis powers in April 1941, and anti-Axis resistance continued until the end of the war.

Associated powers and other states fighting Axis

The Paris peace treaties of 1947 separated "Associated Powers" of the Allies from enemy states that switched sides and became "co-belligerents" of the Allies, or otherwise "took an active part in the war against Germany."

Main article: Albania in World War II

Main article: Bulgaria in World War II

Main article: Lapland War

Italy invaded Albania on 7 April 1939 and took over the country. King Zog of Albania fled to London, but Britain accepted the Italian takeover. Resistance groups, including the Balli Kombëtar and partisans led by the Communist Party, later formed. After Italy left the Axis in September 1943, Germany invaded Albania. In late 1944, Germany left the country, pushed out by partisans who had Allied support. The National Liberation Movement then took control. Albania was recognized as an Associated Power in its 1947 peace treaty with Italy.

Bulgaria joined the Tripartite Pact in 1941 and declared war on the United Kingdom and the United States that December. In 1944, as the Soviet army reached its border, Bulgaria declared war on Germany. Its new communist-dominated government sent over 300,000 troops to fight Germany. Bulgaria stayed technically at war with the Allies until its 1947 treaty with them took effect. Finland was invaded by the Soviet Union in November 1939 and gave up territory in the subsequent peace treaty of March 1940. In 1941 Finland joined Germany's invasion of the Soviet Union, and the United Kingdom declared war on Finland. In 1944 Finland made peace with the Soviet Union through the Moscow Armistice and fought German troops who were leaving the country in the warfare in the Lapland region. Finland was not recognised as an Allied power, and it stayed technically at war with the Soviet Union and the United Kingdom until its 1947 peace treaty.

Italy

Main article: Italy in World War II

Italy entered the war as an Axis power on 10 June 1940. After the Allies invaded Sicily, Italy's fascist leader Benito Mussolini was removed on 25 July 1943, and King Victor Emmanuel III appointed Pietro Badoglio as prime minister. The new government signed an armistice on 3 September 1943, ending Italy's war against the Allies. Italy then declared war on Germany and became a co-belligerent of the Allies. The Italian Co-Belligerent Army fought alongside the Allies against German forces and Mussolini's Italian Social Republic in northern Italy.

Romania was neutral at first but joined the Axis when it signed the Tripartite Pact in November 1940. In 1944, as the war turned against the Axis, King Michael of Romania removed the government of Ion Antonescu, and Romania entered the war against Germany and Hungary. Romania signed an armistice with the Allies in September 1944 and helped the Soviet Union push Axis forces out of the region. Romania remained formally at war with the Allies until its 1947 peace treaty took effect.

Main article: Romania in World War II

Legacy

See also: Aftermath of World War II

Main article: Charter of the United Nations

On 1 January 1942, the Declaration by United Nations was signed by the Four Policemen, which were the United States, United Kingdom, Soviet Union, and China, along with 22 other countries. It laid the groundwork for the future United Nations. At the Potsdam Conference in 1945, Harry S. Truman, Roosevelt's successor, proposed that foreign ministers of five countries should draft peace treaties for Europe. This led to the Council of Foreign Ministers and to those countries becoming permanent members of the UNSC. The Charter of the United Nations was agreed during the war at the United Nations Conference on International Organization, and it was signed by 50 states in June 1945. It was formally ratified shortly after the war, on 24 October 1945. The Dumbarton Oaks Conference in 1944 helped decide the formation of the United Nations Security Council and its permanent seats.

Main article: Cold War

Despite the successful creation of the United Nations, the alliance of the Soviet Union with the United States and with the United Kingdom eventually broke down. It developed into the Cold War, which lasted for the following half-century.

Summary

The Allies had a group of main countries called the Big Four. Many other countries joined them at different times, and some helped as governments in exile or as associated powers.

The Big Four:

• United Kingdom (from 3 September 1939)
  • India
  • Australia
  • New Zealand
  • South Africa
  • Canada
• Soviet Union (from 22 June 1941)
• United States (from 7 December 1941)
• China (from 9 December 1941)

Allied combatant states and governments in exile:

• Free France
• Poland
• Czechoslovakia
• Belgium
• Luxembourg
• Netherlands
• Norway
• Greece
• Yugoslavia
• Ethiopian Empire
• Philippines

Minor sovereign Allied combatant states:

• Mexico
• Brazil

Associated powers of the Allies:

• Nepal
• Albania (from 20 October 1944)

Co-belligerent states fighting the Axis:

• Italy (from 8 September 1943)
• Romania (from 25 August 1944)
• Bulgaria (from 5 September 1944)
• Finland (from 15 September 1944)
• Hungary (from 30 December 1944)

Timeline of Allied states entering the war

Main article: Declarations of war during World War II

Countries joined the Allies at different times. Poland was one of the first, declaring war on 1 September 1939. France followed on 3 September 1939, and the United Kingdom joined on the same day. Several countries in Europe and elsewhere joined in 1940, and Yugoslavia joined on 6 April 1941.

In 1941, the Soviet Union joined on 22 June. The United States declared war on Japan on 8 December 1941, after the Pearl Harbor attack. Many countries in the Americas and China also joined in December 1941. Over the next few years, more countries joined, including several in South America in 1945. Some former Axis powers, such as Italy, changed sides and joined the Allies.