At the conference, Churchill, Stalin and Roosevelt also agreed to create the United Nations according to the principles developed at the Moscow conference. This conference would lead to the pooling of experts. The conference was scheduled to take place on November 28, 1943 at 16.m. Stalin arrived early, followed by Roosevelt, who brought his wheelchair from his apartment next to the place. Roosevelt, who had travelled 11,000 km and whose health was already deteriorating, met Stalin for the first time. Churchill, who was walking with his staff from the nearby shelters, arrived half an hour later. Although Stalin accepted the aforementioned agreements, he dominated the conference. He took advantage of the prestige of the Soviet victory in the Battle of Stalingrad to win. Roosevelt tried to cope with The influx of Stalin`s demands, but could not do much except appease Stalin. Churchill argued for the invasion of Italy in 1943, then overlord in 1944, on the grounds that Overlord was physically impossible in 1943 due to a lack of navigation and that it was unthinkable to do anything until it could be put on the market.
 An important agreement that was reached at the Tehran conference was the agreement between Britain and the United States to open a second front in Europe to reduce pressure on the Soviet Union fighting the Nazis on the Eastern Front. A second agreement from Tehran was the support of the Soviet Union in the fight against Japan, but the condition was the successful defeat of Germany first. Churchill proposed a meeting in London. Stalin insisted on meeting in Tehran, despite the distance Roosevelt and Churchill had to travel. Stalin, who was flying for the first time in his life, arrived first. Roosevelt and Churchill arrived from Cairo where a conference on Japan and Asia was held. Iran was then occupied by Soviet and British troops. The 22-year-old shah, Mohammad Reza Pahlavi, had only ceremonial powers. Iranian leaders were not informed of the conference until a few days earlier. If Stalin and Churchill paid him a courtesy call, Reza shah would meet Roosevelt at the USSR embassy, where he had agreed to stay. The Reza Shah was not even invited to the ceremonies that took place in the embassies.
The statement of the three heads of state and government at the end of the conference on 1 December 1943 listed the following military conclusions: Roosevelt and Stalin spent much of the conference convincing Churchill to engage in an invasion of France, and finally on 30 November, when Roosevelt announced at lunch that they would launch the invasion in May 1944.  This pleased Stalin, who had urged his allies to open a new front in the West to relieve the pressure on his troops. This decision is perhaps the most critical to come out of this conference, since the desired effect of the liberation of Soviet troops was achieved, which resulted in a Soviet rally and an advance towards Germany, a tide that Hitler failed to contain. Roosevelt secured many of his goals during the conference. The Soviet Union had pledged to join the war against Japan and expressed support for Roosevelt`s plans for the United Nations. Most importantly, Roosevelt believed he had earned Stalin`s trust by proving that the United States was ready to negotiate directly with the Soviet Union and, above all, by guaranteeing the opening of the second front in France until the spring of 1944. Stalin also obtained provisional concessions to Eastern Europe, which were confirmed at subsequent war conferences. Iran has waged war on Germany, a common enemy of the three powers. Stalin, Churchill and Roosevelt raised the issue of Iran`s special financial needs during the war and the possibility of needing assistance after the war. The three powers said they would continue to provide assistance to Iran. The Iranian government and the three powers reach an agreement on respect for Iran`s independence, sovereignty and integrity within the framework of all differences of opinion.