The Molotov–Ribbentrop Pact

Non-aggression and secret spheres of influence

23 August 1939 and September 1939

Germany and the Soviet Union signed a non-aggression treaty on 23 August 1939. A secret additional protocol defined spheres of influence in parts of eastern Europe, including Poland. That September, Germany invaded Poland first, followed by Soviet forces from the east.

The public treaty

The treaty committed both parties to refrain from violence, aggression and attacks against one another. If a third power attacked one of them, the other was not to support that power. These provisions governed their mutual relations; they did not themselves protect neighbouring states’ independence.

What was to remain secret

An additional protocol defined spheres of influence in the event of territorial and political changes in the Baltic region and Poland. It left the continued existence of an independent Poland to future developments and mutual agreement. This was not a public commitment to the right of those countries’ inhabitants to decide their own future.

From agreement to invasions

Germany invaded Poland on 1 September 1939; the Soviet Union invaded from the east on 17 September. The pact and its secret protocol therefore help explain Poland’s catastrophe in 1939. The spheres described in August should not simply be treated as an unchanging map of subsequent borders.

From agreement to war between its signatories

In June 1941 Germany invaded the Soviet Union. The 1939 pact therefore does not describe the two states’ relationship throughout the war. Stalin’s Soviet Union subsequently fought Germany and cooperated with Britain and the United States.

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