On 23 August 1939, the world was shocked to discover that Hitler and Stalin, the most intractable of their enemies at the time, had signed a pact that allowed them to divide Poland between them and gave the Nazi leader complete freedom to concentrate his forces in the West, against France and the United Kingdom. Through this agreement, Europe was to be thrown into war. For a long time, the relationship between Hitler and Stalin was ignored: their mutual fascination, their moves to get closer, the marks of confidence they exchanged and all the benefits they derived from the German-Soviet pact, before resuming their war to the death in June 41 with the "Barbarossa" operation.