Secret documents held by the United Nations claim to show Winston Churchill and his fellow Allied leaders were aware of the Holocaust in 1942 - more than two years earlier than previously thought.
It was previously thought that the Allies were informed of Hitler's extermination program in 1944, as they pushed Germany back towards the war's end, liberating the camps along the way in the summer of 1945.
Now, documents held in the archives of the UN War Crimes Commission - which was established to investigate war crimes committed by the Axis powers and dissolved in 1949 - have been released to the public for the first time, with records dating back to 1943.
Some of the documents suggested the UK, US, and Soviet governments were informed roughly two million Jews had been killed, and five million more were threatened with extermination, in 1942.
However it remains unclear if this knowledge was restricted only to higher echelons of government, for senior Allied commanders who liberated concentration camps at the war's end remained in "utter shock" at learning what had transpired in the camps.