The Non-Aggression Pact with the Soviet Union:
The non aggression pact is a 10 years non military action pact in which nor Germany or the soviet union would fight against each other.
This pact also contains a secret pact which the soviets and the Germans agreed on how to divide Easter Europe .
But Adolf Hitler took this pact as an opportunity in which he did a surprised attack on the soviets so that he could get a clear path to Poland with no army as the soviet union were still trying to recover from the after effects of the battles.