On Febuary 11, 1945, Winston Churchill, Franklin D. Roosevelt and Joseph Stalin concluded the Yalta conference.
Stalin and FDR, with Churchill relegated to a minor role, agreed upon the new configuration of a post-war Europe, and sealed its fate and that of the world for the next 45 years.
FDR, who was extremely eager to please his murderous Soviet friend in order to win his cooperation in the war against Japan, agreed to almost anything that Stalin put forward. Stalin's demands were simple, he wanted central and eastern Europe to become part of his Soviet empire.
Stalin would get Bulgaria, Romania, Lithuania, Estonia, Latvia, Czechoslovakia Ukraine, Belarus, Eastern Germany, Moldova, Yugoslavia, Hungary and Poland.
One of the biggest and most controversial issues that were agreed upon in this conference was the fate of post war Poland.
Churchill and FDR had agreed in principle to sell out and backstab their most loyal and staunchest ally in the war against Nazi Germany, Poland, to the worst mass murderer in recorded history.
The "Big three" in Yalta in 1945.
During the war Poland was an ally that was the most loyal to the cause of defeating Hitler and Nazi Germany. An ally which never cooperated in any way with the Nazi regime despite being under brutal occupation. An ally that had hundreds of thousands of soldiers fighting for the allied cause. An ally that had 6 million of its citizens murdered by Nazi Germany and its whole country looted and destroyed. And most importantly, an ally that had signed treaties with the western powers guaranteeing its sovereignty and independence at the end of WW2.
Poland's independence, sovereignty and territorial integrity were the reason why UK and France declared war on Gemany and started WW2 in the first place. But now that the war was all but over, all of those treaties, alliances, pledges and promises were thrown to the dustbin of history, along with Poland.
In fact, Most of the matters concerning Poland and its post WW2 fate were already agreed upon in 1943 in the Tehran conference, in secret, and without the knowledge of the Polish government in exile.
Hundreds of thousands of Poles who fought on the allied side and helped it defeat Nazi Germany, including the Polish pilots that helped save the UK from a German invasion during the "Battle for Britian", would never be allowed to return back to their homes, and were condemned to a life in exile in the UK and Western Europe.
Polish RAF pilots.
The Yalta conference was in effect a criminal and monstrous cold blooded betrayal of one of the key allies in the war against Hitler, a betrayel that was made even worse by the fact that the Polish government had no idea about what was going on at the time, and only found out about it later, when it was too late to do anything about it.
Poland was now repaid for its loyalty, bravery, sacrifices and heroic stance against Hitler and the Nazis with a new murderous Russian occupation that would go on for almost 45 years, an occupation that many people in Poland judged worse than the German one.
Norman Davies, "No simple victory."
Laurence Rees, "World War II Behind Closed Doors: Stalin, the Nazis and the West".