The Tehran Conference (codenamed Eureka[1]) was a strategy meeting of the Allies of World War II, held between Joseph Stalin, Franklin D. Roosevelt, and Winston Churchill from 28 November to 1 December 1943.

In addition to this decision, the Tehran Conference also addressed: the Big Three's relations with Turkey and Iran, as the former was being pressed to enter the conflict and the latter was under Allied occupation; operations in Yugoslavia and against Japan; and the envisaged settlement following the expected defeat of the Axis powers.

Communications regarding those matters between Churchill, Roosevelt, and Stalin took place by telegrams and via emissaries, but it was evident that direct negotiations were urgently needed.

Churchill was an avid traveller and, as part of an ongoing series of wartime conferences, had already met with Roosevelt five times in North America and twice in Africa and had also held two prior meetings with Stalin in Moscow.

Stalin was accompanied by Soviet Minister of Foreign Affairs Vyacheslav Molotov and military leader Kliment Voroshilov.

Churchill brought Foreign Secretary Anthony Eden his CGS Alanbrooke, chief military assistant Hastings Ismay plus Dill, Cunningham, Portal, Boyle, and his interpreter Arthur Birse.

In order to compensate Poland for the resulting loss of territory, the three leaders agreed to move the German-Polish border to the Oder and Neisse rivers.

[7]The leaders then turned to the conditions under which the Western Allies would open a new front by invading northern France (Operation Overlord), as Stalin had pressed them to do since 1941.

Until then, Churchill had advocated the expansion of joint operations of British, American, and Commonwealth forces in the Mediterranean, as opening a new western front had been physically impossible because of a lack of existing shipping routes.

Churchill's plan involved a border along the Oder and the Neisse, which he views to give Poland a fair compensation for the Eastern Borderlands.

Roosevelt had asked to be excused from any discussion of Poland, stating it as matter for the effects of any decision on Polish voters in the US and the upcoming 1944 election.

Soon before the conference, the USSR unilaterally withdrew recognition of the Polish government-in-exile, still recognized by the UK and the US and the negotiations were made covertly without their involvement.

During the negotiations, Roosevelt had demanded that the Republics of Lithuania, Latvia, and Estonia would be deemed as part of the Soviet Union only after the citizens 'voted' on the action.

Roosevelt secured formal 'agreement', however, Stalin would not consent to any international control over the elections and stated that all issues would have to be resolved 'in accordance with the Soviet Constitution'.

[22] The numbers that were proposed varied widely and never came to fruition, but the powers would effectively divide modern Germany into two parts until the end of the Cold War.

"[23] On 29 November, Roosevelt asked Stalin five questions about data and intelligence relating to Japanese and Siberian ports and about air bases in the Maritime Provinces for up to 1,000 heavy bombers.

However, Roosevelt wanted to avoid the appearance of choosing one ally over another and decided it was important to stay at the American legation to remain independent.

Mike Reilly, Roosevelt's chief of Secret Service, advised him to move to either the Soviet or British embassies for his safety.

One of the underlying factors influencing their decision was the distance Churchill and Stalin would need to travel for meetings at the American legation.

Harriman reminded the President that the Americans would be held responsible if Stalin or Churchill were assassinated while traveling to visit Roosevelt all the way across the city.

The timing of Molotov announcing an assassination plot later that night aroused suspicion that his motives were to keep Stalin safely within the guarded walls of the Soviet embassy.

[25] Harriman doubted the existence of an assassination plot, but urged the President to relocate to avoid the perception of putting Churchill and Stalin in danger.

Molotov's response minimized their assertions of an assassination plot, instead emphasizing that Stalin thought President Roosevelt would be safer at the Soviet embassy.