In November 1943, the Big Three (the USSR, US, and UK) met at the Tehran Conference. President Roosevelt and PM Churchill officially agreed that the eastern borders of Poland would roughly follow the Curzon Line. The Polish government-in-exile was not a party to this decision made in secret. The resulting loss of the Kresy, or "eastern territories", approximately 48% of Poland's pre-war territory, to the Soviet Union was seen by the London Poles in exile as another "betrayal" by their Western "Allies". However, it was no secret to the Allies that before his death in July 1943 General Władysław Sikorski, Prime Minister of Poland's London-based government in exile had been the originator, and not Stalin, of the concept of a westward shift of Poland's boundaries along an Oder–Neisse line as compensation for relinquishing Poland's eastern territories as part of a Polish rapprochement with the USSR. Józef Retinger, who was Sikorski's special political advisor at the time, was also in agreement with Sikorski's concept of Poland's realigned post-war borders, later in his memoirs Retinger wrote: "At the Tehran Conference, in November 1943, the Big Three agreed that Poland should receive territorial compensation in the West, at Germany's expense, for the land it was to lose to Russia in Central and Eastern Europe. This seemed like a fair bargain."