Casablanca was the first of the conferences, in 1943. Stalin, however, did not attend this meeting. It was at this meeting that the term unconditional surrender first came about. The leaders agreed that the Axis could only surrender in an unconditional form.
Iosif Stalin first met Churchill and Roosevelt in Teheran, November and December 1943. At this conference, it was agreed that the UK and the US would invade Germany. Also, it was decided that the USSR would help in the invasion of Japan. Post war Polish frontiers were also discussed at this time.
German forces were declining by the time the Quebec meeting of August 1944 was held. Here, the leaders stress again plan for defeating Japan. They also made plans about a free French Government and for dividing Germany into four parts.
Yalta and 1945 brought the plans for the finalization of the occupation of Germany and its division into four parts. These were going to be controlled by Great Britain, United States, The Soviet Union, and France. The three agreed upon a provisional government for Poland.
A few months after the Yalta conference, Franklin Roosevelt died. Harry Truman, the vicepresident, assumed the presidency of the United States. Truman, Stalin, Churchill decided Germany 's fate at the Potsdam conference in August 1945 and issued ultimatum to Japan.
Before all three conferences, the powers made pacts with each other. At Yalta, Roosevelt gave away Eastern Europe to USSR, although Great Britain did not agree completely with this. "Critics would accuse Roosevelt of a "sell-out " at Yalta, of giving away Eastern Europe to Stalin, of "secret deals " with a ruthless dictator. Bert Andrews in the New York Herald Examiner wrote about four secret deals: Russia 's demand for $20 billion in reparations from Germany, for Poland to the Curzon line, for 3 seats in the United Nations, for territory in the Far East including Outer Mongolia, south Sakhalin Island, the Kurile
At the Potsdam conference, among other things decided, the damage of war was also discussed. All three powers agreed to make Germany unable of starting a war conflict ever again as well as making it pay war damage. Germany's satellite countries, on the other hand, just had to pay for reparations. "The Berlin (Potsdam) Conference, July 17-August 2, 1945 (a) Protocol of the Proceedings, August l, 1945
B. ECONOMIC PRINCIPLES.
11. In order to eliminate Germany 's war potential, the production of arms, ammunition and implements of war as well as all types of aircraft and sea-going ships shall be prohibited and prevented. Production of metals, chemicals, machinery and other items that are directly necessary to a war economy shall be rigidly controlled and restricted to Germany 's approved post-war peacetime needs to meet the objectives stated in Paragraph 15. Productive capacity not needed for permitted production shall be removed in accordance with the reparations plan recommended by the Allied Commission on Reparations and approved by the Governments concerned or if not removed shall be destroyed. ( . )
XI. REVISED ALLIED CONTROL COMMISSION PROCEDURE IN RUMANIA, BULGARIA, AND HUNGARY.
The three Governments took note that the Soviet Representatives on the Allied Control Commissions in Rumania, Bulgaria, and Hungary, have communicated to their United Kingdom and United States colleagues' proposals for improving the work of the Control Commissions, now that hostilities in Europe have ceased.
The three Governments agreed that the revision of the procedures of the Allied Control Commissions in these countries would now be undertaken, taking into account the interests and responsibilities of the three Governments which together presented the terms of armistice to the respective countries, and accepting as a basis, in respect of all three countries, the Soviet Government 's proposals for Hungary as annexed hereto. " (https://www.yale.edu/lawweb/avalon/decade/decade17.htm)
At Yalta the Leaders agreed that the Axis countries would have to pay $ 20,000,000,000 for reparations. Of this, half went to USSR. It was a fare price, since the Russians had almost half (20,000,000) of the 55,000,000 casualties of World War II. "It was agreed at Yalta that the sum of $20,000 million should be taken as a basis for further discussions, half of it being claimed by USSR for itself and Poland. At Potsdam, the Russians, whose need for reparations in kind of cash was intense, secured agreement for removals from their zone of occupation to meet Russian and Polish reparation claims, but nothing was settled about the extent of the claims. The western allies were likewise to be entitled to dismantle and remove property in their zones in order to meet their claims and those of the remaining allies." (Peter Calvocoressi, World Politics Since 1945, sixth edition, Longman Publishers, page 15)
The situations that emerged from the Potsdam and Yalta conferences were the same: Europe would be divided into two influence spheres. Roosevelt and Churchill, however, could only agree to the influence zones, since the Russian army was already in these countries. The "Iron Curtain" was the demarcation line between the Occident and the countries of Central and Eastern Europe. East of the Iron curtain you could find Poland, Yugoslavia, Czechoslovakia, Hungary, Romania, Bulgaria, the USSR and Eastern Germany. "It has been argued that the division of Europe and the resulting Russian overlordship in Eastern Europe were the consequence not of historical accident, but of agreement, notably agreement at Yalta by Roosevelt and Churchill to give Stalin a position of power which otherwise he could not have achieved. This argument cannot be sustained. Roosevelt and Churchill conceded at Yalta nothing that it was in their power to withhold. The Russians armies were already in occupation of positions in Europe from which they could not be expelled ( . ) [Stalin] created a satellite empire in witch the component states retained their separate juristic identities ( . ) but were subjected to Russian purposes by the realities of Russian military power and the modalities of Communist Party and police rule and unequal economic treaties. There was soon little difference between former foes like Hungary, Romania and Bulgaria, and wartime allies like Poland, Czechoslovakia and Yugoslavia." (Peter Calvocoressi, World Politics Since 1945, sixth edition, Longman Publishers, page 231)
Before the Potsdam conference, the US senators who had recently visited Europe believed that most of the continent would change democracy for communism after the war.