Molotov–Ribbentrop Pact

In August 1939 the two great ideological enemies of interwar Europe, Nazi Germany and the Soviet Union, promised not to attack each other. Their foreign ministers, Vyacheslav Molotov and Joachim von Ribbentrop, signed the treaty in Moscow. Dated 23 August 1939, though actually signed on 24 August, it was followed a week later by Germany's invasion of Poland. A secret protocol divided Eastern Europe between the two dictatorships, and its existence was officially denied by Moscow for half a century.

Nazi ideology was violently hostile to communism and regarded Slavs as racially inferior, and the Nazis' rise to power in the early 1930s strained relations between the two states. In 1938 the Soviet Union was left out of the Munich Agreement, which handed part of Czechoslovakia to Germany, and its later talks with Britain and France on a defensive alliance made little progress. From early 1939, Berlin and Moscow cautiously moved closer. A commercial agreement was concluded on 19 August. Talks with the British and French missions in Moscow broke down on 21 August, and the next day the Soviets announced that Ribbentrop was coming.

The published treaty bound both countries for ten years not to attack each other, to stay neutral if the other went to war with a third power, and not to join any group aimed against the other. At the signing, Ribbentrop and Joseph Stalin exchanged toasts and friendly remarks.

The secret additional protocol went much further. It assigned Finland, Estonia and Latvia to the Soviet sphere of influence and Lithuania to the German one, and provided that Poland would be partitioned along the Narew, Vistula and San rivers. It also recognised Soviet interest in Bessarabia, then part of Romania. A further treaty on 28 September 1939 moved almost all of Lithuania into the Soviet sphere and gave Germany a larger share of Poland.

Germany invaded Poland on 1 September 1939, a week after the signing. Soviet troops crossed into eastern Poland on 17 September, and after Poland's defeat the two powers fixed a new border across its territory. The Soviet Union then attacked Finland in the Winter War, gaining parts of Karelia and other land in March 1940. In 1940 it annexed Estonia, Latvia and Lithuania, and took Bessarabia and Northern Bukovina from Romania; Northern Bukovina lay outside the agreed Soviet sphere. Meanwhile a large trade agreement of February 1940 sent Soviet grain, oil and other raw materials to Germany, helping it to withstand the British blockade.

The partnership ended on 22 June 1941, when Germany invaded the Soviet Union in Operation Barbarossa.

Rumours of the secret protocol circulated from the start, but proof emerged only after the war. A microfilm copy of German Foreign Office records survived, and the protocol's contents were first raised at the Nuremberg trials, where Ribbentrop was convicted and later hanged. The United States published the texts in January 1948. The Soviet Union nevertheless denied that the protocol existed until December 1989, when the Congress of People's Deputies, after an inquiry ordered under Mikhail Gorbachev, acknowledged and condemned it. Molotov himself denied it until his death in 1986.

Many of the territorial changes outlasted the war: the eastern Polish lands remained Soviet and today belong to Ukraine and Belarus, and much of Bessarabia now forms Moldova. On 23 August 1986, demonstrators in many Western cities held Black Ribbon Day rallies, and in 2009 the European Parliament declared 23 August a day of remembrance for the victims of Stalinism and Nazism. In Russia, official accounts have often presented the pact as a defensive necessity.

Our 1938 map shows Poland, the Baltic states and Romania before the pact, and the 1945 map shows the new frontiers drawn after the war.