Tehran Conference

1. Lead

The first meeting of the Big Three

The Tehran Conference, held from 28 November to 1 December 1943 in the Soviet embassy in Tehran, Iran, was the first meeting of the three leaders who directed the Allied war effort: President Franklin D. Roosevelt of the United States, Prime Minister Winston Churchill of Britain, and Premier Joseph Stalin of the Soviet Union.

Codenamed Eureka, it was the first of the great wartime conferences at which all three were present together, and it produced the single most important strategic decision of the war in Europe: the Western Allies committed themselves to opening a second front by invading northern France in the spring of 1944, in an operation that would become D-Day and Operation Overlord.

Stalin, in return, promised a great Soviet offensive on the Eastern Front to coincide with the landings, and agreed that the Soviet Union would enter the war against Japan once Germany was defeated.

Why Tehran still matters

Tehran mattered for more than the second front. It was the conference at which the shape of post-war Europe began to be drawn: the three leaders discussed the future borders of Poland, the treatment of Germany after its defeat, and the creation of a new international organisation to replace the failed League of Nations — the body that would become the United Nations.

It was also the conference that revealed, for the first time in person, the temperaments and the tensions of the three men: Roosevelt’s desire to win Stalin’s trust, Churchill’s determination to protect the British Empire and to keep the Mediterranean at the centre of Allied strategy, and Stalin’s blunt, relentless pursuit of Soviet security.

The decisions taken at Tehran were carried out, by and large, as agreed — the landings in France took place on 6 June 1944, and the Soviet offensive followed — but the understandings reached there about Poland and Eastern Europe would become, within a few years, the first disputes of the Cold War.

2. Key Facts

Date	28 November – 1 December 1943
Location	Soviet embassy, Tehran, Iran
Codename	Eureka / Eureka
Participants	Franklin D. Roosevelt (United States); Winston Churchill (Britain); Joseph Stalin (Soviet Union)
Main decision	Open a second front in northern France (Operation Overlord) in May 1944; a simultaneous Soviet offensive on the Eastern Front
Other decisions	Soviet Union to enter the war against Japan after Germany’s defeat; Polish borders to shift westwards (Curzon Line in the east, Oder–Neisse in the west); support for the Yugoslav Partisans; Declaration on Iran
Followed by	Yalta Conference (February 1945) and Potsdam Conference (July–August 1945)

3. Background

Two years of waiting for a second front

By the autumn of 1943, the Soviet Union had been fighting Germany alone on land in Europe for more than two years, since the German invasion of June 1941, and it had paid a terrible price. Tens of millions of Soviet soldiers and civilians had been killed, and the German armies still occupied a vast area of Soviet territory.

Since 1941 Stalin had demanded, with increasing insistence, that Britain and the United States open a second front in Western Europe — a large-scale invasion of France that would force Germany to divide its armies between east and west. The Western Allies had promised a second front, but they had not delivered one.

Instead, in 1942 and 1943, they had invaded North Africa, then Sicily, then Italy — campaigns that Churchill favoured, because they attacked what he called the “soft underbelly” of Europe, but which Stalin regarded as a diversion from the real task.

The suspicion that Britain and America were content to let the Soviet Union bleed while they fought on the periphery was one of the deepest sources of mistrust within the alliance, and it was the issue Stalin was determined to settle at Tehran.

The road to Tehran

The conference was preceded by months of negotiation about where and when the three leaders would meet. Stalin refused to travel far from Moscow, because he would not leave the Soviet Union while the war was at its height, and he refused to meet in a place that was not under Soviet control.

Tehran was the compromise: the capital of Iran, which had been occupied jointly by Britain and the Soviet Union since 1941, and a city where the Soviet embassy could provide both the venue and the security. Roosevelt travelled to Tehran by way of Cairo, where he and Churchill had just met the Chinese leader Chiang Kai-shek at the Cairo Conference, and where Churchill had argued, once again, for delaying the invasion of France in favour of further operations in the Mediterranean.

By the time the three men arrived in Tehran on 28 November, the central question was already clear: would the Western Allies commit, finally and irrevocably, to invading France in 1944, or would they ask Stalin to wait another year?

4. Opposing Forces

Three different wars

The three leaders at Tehran were, in a sense, fighting three different wars. For Stalin, the war was a struggle for the survival of the Soviet Union, fought on Soviet soil against an enemy that had killed millions of his people, and the only strategy that mattered was the one that would kill Germans fastest.

For Churchill, the war was a struggle for the survival of the British Empire and for Britain’s position as a great power, and he believed that the Mediterranean, the Balkans and the defence of British interests in the Middle East and India were as important as the invasion of France.

For Roosevelt, the war was a struggle to build a new world order — a United Nations, an end to colonial empires, and an American-led peace — and he believed that the key to that order was a lasting partnership with the Soviet Union, which meant that Stalin’s trust had to be won, even at the cost of overruling Churchill.

These different wars produced different priorities at Tehran, and the conference was, in large part, a negotiation between them.

The balance of power in the room

	United States	Britain	Soviet Union
Leader	Franklin D. Roosevelt, President	Winston Churchill, Prime Minister	Joseph Stalin, Premier
Main demand	A post-war United Nations; Soviet cooperation against Japan	Delay Overlord; continue in the Mediterranean; protect the Empire	A second front in France in 1944; secure western borders
Strength at the table	The largest industrial power; the main supplier of Lend-Lease aid	The most experienced war leader; the Mediterranean position	The largest land army; bearing the main burden of the fighting
Weakness	No large army yet in combat in Europe	Dependent on American supplies; an empire under strain	Desperate for a second front; dependent on Allied aid

In the room, the balance of power was shifting. Britain, which had stood alone in 1940, was now the junior partner of the alliance, dependent on American money and supplies. The United States, which had entered the war only two years earlier, was now the dominant economic power and the arsenal of the alliance. The Soviet Union, which had borne the greatest human cost, had the largest army in the field and a leader who knew it. Roosevelt understood this, and he acted accordingly: at Tehran, on the central question of the second front, he sided with Stalin against Churchill, and the decision was made.

5. The Battle

The second front, at last

The first full session of the conference, on 28 November, was dominated by the second front. Stalin opened by asking, bluntly, when the invasion of France would take place, and who would command it. Churchill replied with a long exposition of the difficulties — the shortage of landing craft, the need to continue the campaign in Italy, the possibility of operations in the Balkans — and proposed that the invasion might be delayed until the summer of 1944 or later.

Stalin, who had heard these arguments before, replied that the invasion must take place in May 1944, and that the Mediterranean operations were a distraction. The argument continued through 29 November, with Roosevelt largely silent, listening to both men. On 30 November, at lunch, Roosevelt announced the decision: the invasion of France — Operation Overlord — would be launched in May 1944. Churchill, outvoted, accepted.

The date was later adjusted: the final agreement, recorded in the military conclusions of the conference signed on 1 December, set the invasion for May 1944, with the understanding that it might slip into June, as in the event it did — the landings took place on 6 June 1944.

Stalin, for his part, promised a great Soviet offensive on the Eastern Front at about the same time, to prevent Germany from transferring troops westwards. The offensive that followed, Operation Bagration in June 1944, was the greatest Soviet operation of the war, and it destroyed the German Army Group Centre.

The date and the commander

The agreement on the date was accompanied by an agreement on the command. Stalin insisted on knowing who would command Overlord, because he believed — rightly — that a commander who had not yet been named was a sign that the operation was not yet real. Roosevelt had not yet chosen, and it was only after Tehran, in December 1943, that he appointed General Dwight D. Eisenhower to the command.

The delay in naming the commander was one of the reasons Stalin had doubted Western intentions, and the appointment, when it came, was taken in Moscow as proof that the decision at Tehran was serious. Roosevelt’s choice was not a foregone conclusion.

The other candidate was General George Marshall, the Chief of Staff of the United States Army, whom many expected to receive the command, but Roosevelt decided that Marshall was too valuable in Washington, where he directed the whole American war effort, and that Eisenhower, who had commanded the landings in North Africa and in Sicily, was the right man for the invasion of France.

Eisenhower took up his post in January 1944, and he remained in command of Overlord until the end of the war in Europe.

The southern France landing

Tehran also settled the question of a second landing in southern France, Operation Anvil (later renamed Dragoon), which Stalin supported and Churchill opposed. The conference agreed that a landing in southern France would take place at about the same time as Overlord, to support the main invasion. In the event, the southern landing was delayed until August 1944, because the landing craft and troops were needed in Normandy first, but when it came it was a success, and it provided the Allies with the great port of Marseille.

Poland, Germany and the post-war order

The second great subject of the conference was the map of post-war Europe. Stalin pressed for the Soviet Union’s western border to be moved to the line proposed by the British Foreign Secretary Lord Curzon in 1920 — the Curzon Line — which would give the Soviet Union a large area of eastern Poland.

To compensate Poland for this loss, the three leaders agreed that Poland’s western border should be moved to the rivers Oder and Neisse, at Germany’s expense. The effect was to shift the whole of Poland westwards by some 200 kilometres: Poland would lose its eastern territories to the Soviet Union and gain German territory in the west.

The Polish government-in-exile in London, which had not been consulted, was not told of the decision at the time, and the decision would remain a source of bitterness for decades. The conference also discussed the future of Germany, in general terms: all three leaders agreed that Germany should be weakened and divided in some way, though no detailed plan was adopted, and the question was left for later conferences.

Roosevelt also raised his proposal for a new international organisation — the United Nations — and Stalin, after some discussion, agreed in principle to Soviet participation. The Declaration on Iran, signed separately, pledged the three powers to respect Iran’s independence and territorial integrity, and to provide economic assistance to the country — a promise that, like several others made at Tehran, would be honoured more in the letter than in the spirit.

The dinner-table incident

The most famous, and the most disputed, episode of the conference took place at dinner on 29 November. According to Churchill’s memoirs, Stalin proposed, apparently in earnest, that 50,000 to 100,000 German officers should be executed after the war, so that Germany could never again plan a war.

Churchill, horrified, replied that he would rather be taken out and shot himself than dishonour his country by such an act, and left the table. Roosevelt, attempting to defuse the tension, is said to have suggested, jokingly, that they compromise on 49,000. Stalin and his foreign minister, Vyacheslav Molotov, are reported to have laughed.

Historians disagree about how seriously Stalin meant the proposal: some believe it was a grim joke, designed to provoke Churchill; others believe it reflected a real Soviet view. What is not disputed is that the episode revealed, in a single evening, the gulf between the Western leaders, who insisted that war criminals should be tried by law, and Stalin, who regarded such questions as matters of power.

The question of war criminals was left unresolved at Tehran, and it would be settled, after the war, by the trials at Nuremberg.

6. Turning Point

Roosevelt’s lunch-time decision

The turning point of the Tehran Conference was Roosevelt’s announcement at lunch on 30 November that Operation Overlord would be launched in May 1944. Until that moment, the conference had been drifting: Churchill had argued for delay, Stalin had demanded a date, and Roosevelt had listened without committing himself. The lunch-time announcement settled the matter.

It was the moment at which the United States, the dominant power of the alliance, chose the Soviet demand over the British preference, and it was the moment at which the second front became a certainty rather than a promise. From that point onwards, the conference was about details — the southern France landing, the Soviet offensive, Poland — rather than about whether the invasion would happen at all.

The decision also settled the strategic shape of the rest of the war: the main Allied effort in Europe would be the invasion of France, supported by a Soviet offensive in the east, and the Mediterranean would become a secondary theatre.

The price of the decision

The decision had a price, and it was paid in the agreements on Poland. Stalin’s support for Overlord, and his promise of a Soviet offensive and of war against Japan, were not given freely: they were exchanged for Western acceptance of the Curzon Line and of the westward shift of Poland.

Roosevelt and Churchill accepted, in part because they believed that the Soviet Union would take the territory in any case, and in part because they believed that the friendship of the Soviet Union was worth the price. The judgement of history on that bargain has been harsh: the Polish people, who had fought alongside the Allies from the first day of the war, lost their eastern lands and, within a few years, their independence as well, as Poland fell under Communist rule.

Tehran was, in this sense, the first of the conferences at which the Western Allies accepted a Soviet fait accompli in Eastern Europe — a pattern that would be repeated at Yalta and at Potsdam, and that would define the Cold War map of Europe for more than forty years.

7. Casualties and Losses

A conference, not a battle

The Tehran Conference was a meeting, not a battle, and no one was killed or wounded in Tehran itself. There is no casualty table for the conference, and it would be misleading to invent one. But the conference was about a war in which the casualties were counted in tens of millions, and its decisions had direct consequences for the human cost of the war’s last eighteen months.

The decision to invade France in 1944, rather than to delay the invasion or to continue the Mediterranean strategy, meant that the great battles of 1944 and 1945 — Normandy, the breakout, the Ardennes offensive, the crossing of the Rhine — would be fought on the timetable agreed at Tehran.

The casualties of those battles, on all sides, were the price of the strategy Tehran chose, and they were heavy: the Normandy campaign alone cost the Allies tens of thousands of dead, and the Soviet offensive of the summer of 1944, Operation Bagration, cost the Soviet Union hundreds of thousands of casualties even as it destroyed an entire German army group.

The human cost of the Polish decision

The conference’s decisions on Poland also had a human cost, though of a different kind. The westward shift of Poland’s borders, agreed at Tehran and confirmed at Yalta and Potsdam, led to one of the largest forced movements of people in European history.

Millions of Germans were expelled from the territories east of the Oder and Neisse that were transferred to Poland, and millions of Poles were moved from the eastern territories annexed by the Soviet Union to the new western territories. Estimates of the number of people who died during these expulsions vary widely — historians give figures in the hundreds of thousands — and the figures remain a subject of dispute, in part because the records are incomplete and in part because the expulsions took place in the chaos of the war’s end.

This article does not present a single figure as certain. What is certain is that the decision taken by three men in Tehran, about lines on a map, had consequences for millions of ordinary people who had no voice in the room.

8. Map and Geography

Tehran, a city between empires

Tehran in 1943 was the capital of a country that was itself a product of great-power rivalry. Iran lay between the British Empire in India and the Soviet Union, and it had been occupied jointly by British and Soviet forces since August 1941, when the two powers invaded to secure the country’s oil and the supply route — the Persian Corridor — by which American Lend-Lease aid reached the Soviet Union.

The conference was held in the Soviet embassy compound, a walled enclave in the centre of the city, and Roosevelt, at Stalin’s invitation, stayed in the Soviet embassy itself, rather than in the American legation across the city — a decision that was both a matter of security, since the city was thought to be full of German agents, and a matter of symbolism, since it placed the American President, literally, on Soviet ground.

The British legation was nearby, and the three leaders could move between the embassies without passing through the city. The geography of the conference — three embassies within a few hundred metres of each other, in a city under joint occupation — was itself a map of the alliance: three powers, close together, but each on its own ground.

The map the conference drew

The map that Tehran drew was the map of post-war Europe. The Curzon Line in the east and the Oder–Neisse line in the west shifted Poland westwards; the agreement on Germany, though vague, pointed towards a Germany that would be divided and weakened; and the discussion of the United Nations pointed towards a new world organisation with its headquarters, as Roosevelt hoped, in the United States.

The map was incomplete — the final borders of Germany, the future of the Balkans, and the division of Europe into spheres of influence were left for Yalta and Potsdam — but its outlines were drawn at Tehran. It is a map that can still be read today: the Polish border on the Oder and Neisse, agreed in principle at Tehran, is the border of Poland today, and the division of Europe that began at Tehran lasted until 1989.

9. Outcome and Legacy of the Tehran Conference

What Tehran decided, and what happened next

The decisions of Tehran were, by and large, carried out. Operation Overlord was launched on 6 June 1944, and the Soviet offensive that Stalin had promised, Operation Bagration, began on 22 June 1944, the third anniversary of the German invasion of the Soviet Union.

The two offensives, taken together, broke the German army in the summer of 1944 in a way that no single offensive could have done: Germany, attacked from east and west at the same time, could not transfer its reserves to meet either threat, and by the autumn of 1944 its armies were in retreat on both fronts.

Stalin’s promise on Japan was also kept: the Soviet Union declared war on Japan on 8 August 1945, two days after the atomic bombing of Hiroshima, and its armies overran Manchuria in a campaign that lasted less than two weeks. The United Nations, which Roosevelt had discussed at Tehran, was founded at San Francisco in 1945, and its first headquarters were in the United States, as Roosevelt had hoped.

In the narrow sense of whether the conference achieved what it set out to achieve, Tehran was a success.

The shadow over Tehran’s legacy

The shadow over Tehran’s legacy is Poland. The decision to shift Poland’s borders, taken without consulting the Poles, and the acceptance — implicit at Tehran, explicit at Yalta — that the Soviet Union would dominate Eastern Europe, became the founding grievance of the Cold War.

In the West, Tehran came to be seen, by some, as the conference at which Roosevelt was deceived by Stalin, or at which he gave away too much in exchange for promises that Stalin did not keep. That judgement is too simple: Roosevelt was not deceived about Stalin’s intentions, and he knew that the Soviet Union would take the territory in any case.

But it is true that Tehran marked the moment at which the Western Allies accepted that the liberation of Eastern Europe would be followed by Soviet domination, and that the Europe that emerged from the war would be divided. The conference is remembered, in the end, for both of its faces: the strategic triumph of the second front, and the political bargain that divided a continent.

10. Commanders

The three leaders

Franklin D. Roosevelt (United States). President of the United States from 1933 until his death in April 1945, and the host, in effect, of the conference’s central decision. Roosevelt came to Tehran determined to win Stalin’s trust and to secure Soviet cooperation for the post-war world, and he was willing to overrule Churchill to do it.

He was also the only one of the three leaders who had never met Stalin before, and the conference was, for him, a personal as well as a political encounter. His health was already failing — he would die less than eighteen months later — and some historians have argued that his illness affected his judgement at Tehran and at Yalta, though others dispute this.

Joseph Stalin (Soviet Union). Premier of the Soviet Union and the leader who got most of what he wanted at Tehran: a firm date for the second front, Western acceptance of the Curzon Line, and a free hand, in effect, in Eastern Europe. Stalin was a blunt and formidable negotiator, and he dominated the conference’s substantive discussions. He had insisted on the venue, he controlled the security, and he knew, better than either of his counterparts, what he wanted and what he was prepared to give in exchange.

Winston Churchill (Britain). Prime Minister of the United Kingdom, and the leader who lost the central argument at Tehran. Churchill had argued for the Mediterranean strategy and for delaying Overlord, and he was overruled by Roosevelt and Stalin. He accepted the decision, and he worked to make Overlord a success, but the conference marked the moment at which Britain ceased to be an equal partner in the alliance and became, in effect, the junior partner of the United States. Churchill’s memoirs, published after the war, give the fullest Western account of the conference, including the dinner-table incident.

The men behind the leaders

Vyacheslav Molotov (Soviet Union). The Soviet Foreign Minister, who accompanied Stalin at Tehran and who played a central role in the detailed negotiations, particularly on Poland and on the post-war settlement. Molotov, known in the West as “Mr Nyet” for his habit of saying no, was Stalin’s most trusted diplomat, and he would remain Foreign Minister through the early years of the Cold War.

Anthony Eden (Britain). The British Foreign Secretary, who accompanied Churchill. Eden was deeply suspicious of Soviet intentions in Eastern Europe, and he worked, with limited success, to limit the concessions made to Stalin at Tehran. His opposition to the Morgenthau Plan, in a different context, and his suspicion of Stalin at Tehran, reflected the same instinct: a determination to preserve a balance of power in Europe.

Harry Hopkins (United States). Roosevelt’s closest adviser, who accompanied the President to Tehran and who had earlier visited Moscow as Roosevelt’s personal envoy to Stalin. Hopkins, who was seriously ill himself, was one of the architects of the American policy of cooperation with the Soviet Union, and his presence at Tehran was a sign of how much importance Roosevelt attached to the Soviet relationship.

Frequently Asked Questions

When was the Tehran Conference?
From 28 November to 1 December 1943, in the Soviet embassy in Tehran, Iran.

Who attended the Tehran Conference?
President Franklin D. Roosevelt of the United States, Prime Minister Winston Churchill of Britain, and Premier Joseph Stalin of the Soviet Union — the “Big Three”.

What was the main decision at Tehran?
The Western Allies committed to opening a second front by invading northern France (Operation Overlord) in May 1944, and Stalin promised a simultaneous Soviet offensive on the Eastern Front.

What was decided about Poland at Tehran?
Poland’s eastern border was to follow the Curzon Line, giving eastern Poland to the Soviet Union, and its western border was to move to the Oder and Neisse rivers, at Germany’s expense.

Did Stalin agree to fight Japan?
Yes. At Tehran, Stalin agreed that the Soviet Union would enter the war against Japan once Germany was defeated. The Soviet Union declared war on Japan on 8 August 1945.

Why was Tehran the first Big Three conference?
Because it was the first wartime conference attended by all three leaders together. Earlier conferences had involved only two of them, or their representatives, and Stalin had refused to travel far from Moscow.

Related articles

• Morgenthau Plan
• Axis Powers
• Balkan Wars

Sources

1. Wikipedia, “Tehran Conference” — dates, participants, the second-front decision, the Polish borders and the dinner-table incident.
2. Winston Churchill, The Second World War, Vol. V: Closing the Ring (Houghton Mifflin, 1951) — Churchill’s account of the conference, including the 50,000 officers episode.
3. Encyclopædia Britannica, “Tehran Conference” — summary of the decisions and their consequences.
4. US Department of State, Foreign Relations of the United States: The Conferences at Cairo and Tehran, 1943 — the official American record, including the military conclusions of 1 December 1943.
5. Keith Sainsbury, The Turning Point: Roosevelt, Stalin, Churchill, and Chiang Kai-Shek, 1943: The Moscow, Cairo, and Teheran Conferences (Oxford University Press, 1985).
6. National Archives (UK), CAB 65 and PREM 3 — the British Cabinet and Prime Minister’s papers on Tehran.

Further reading

• Lloyd C. Gardner, Spheres of Influence: The Great Powers Partition Europe, from Munich to Yalta (Ivan R. Dee, 1993).
• Robert Dallek, Franklin D. Roosevelt and American Foreign Policy, 1932–1945 (Oxford University Press, 1979).