It was a conference of the leaders of the Allied countries that was held in early 1945 in order to determine strategies and plans for the final months of World War II and postwar policies
On February 4, 1945, Roosevelt, Stalin and Churchill, leaders of the United States, Soviet Union and Britain started their 8-day negotiations at the Tsar’s Castle in the city of Yalta, at Crimea Peninsula.
In Yalta negotiations, it was decided that Germany be divided into four parts and each part be bestowed to a war victor. The victors were United Stated, Soviet Union, Britain and France. France was added to the list due to some political considerations.
Yalta Conference

The Conference decided that the East European countries and the lands taken out German domination by the Red Army go under the Soviet influence; Yugoslavia be given to Tito, leader of partisans; Austria becomes a free and impartial country. The conference couldn’t decide on Greece.