What was the deal called between Germany and the Soviet Union when dividing up Poland while not attacking each other?

(World War ll / Aftermath of the war)

It is called the Ribbentrop-Molotov Pact, though it is also called the Soviet-German Non-Aggression Pact. It takes its name from the last names of its negotiators and signatories, German foreign minister Joachim von Ribbentrop and Soviet foreign minister Vyacheslav Molotov.

It was signed in August 1939, just weeks before the Nazi invasion of Poland. Both the Third Reich and the Soviet Union assured peace among themselves and divided Poland's territory into two zones. The treaty allowed each state to cover their back; the USSR was not prepared for a war with Germany and did not want to fight alone, and the Third Reich wanted to avoid a two-front war in Europe (the WWI scenario and the nightmare of German strategists), knowing the attack to Poland would most likely lead to war with France and Britain.