On the 23th of August, 1939 (some days before the beginning of WWII) Hitler and Stalin signed a German-Soviet Nonaggression Pact, according to which the two nations would not execute any military attack on each other for 10 years. This was a strategic move on both sides, since Stalin saw it as an opportunity to stay out of conflict and reinforce the Soviet military, and Hitler wanted to invade Poland without opposition. But in 1941, after invading Poland, Germany broke the pact, starting its invasion over Soviet territory. This forced Russia to join the Allies in an effort to stop a very powerful Germany.
Italy and Japan were dissatisfied with the peace settlements provided in the Treaty of Versailles because both countries expected more "<span>c. territory in exchange for their sacrifices during World War I," since they had lost many men. </span>
