Foreign ministers Joachim von Ribbentrop and Vyacheslav Molotov signed the Molotov-Ribbentrop Pact, publicly pledging non-aggression while secretly carving Poland, the Baltic states, and Finland into German and Soviet spheres of influence. The agreement stunned the world, given the ideological hostility between fascism and communism, and freed Hitler to invade Poland just eight days later without fear of Soviet interference.
The pact shocked observers precisely because Nazi Germany and the Soviet Union had spent years denouncing each other as existential enemies. Stalin, distrustful of British and French willingness to confront Hitler after the Munich betrayal of Czechoslovakia, opted instead to buy time and territory through a deal with Berlin. Ribbentrop reportedly found the Kremlin surprisingly warm and the negotiations swift, and Stalin himself toasted Hitler's health at the signing banquet.
The published treaty spoke only of neutrality, but a secret protocol divided Poland roughly along the Vistula, Narew, and San rivers and assigned Finland, Estonia, and Latvia to Soviet influence, with Lithuania added in a later adjustment. Hitler invaded Poland from the west on September 1; the Red Army invaded from the east on September 17, per the secret terms. The pact held until Hitler broke it with Operation Barbarossa in June 1941, but its brief existence reshaped the map and fate of Eastern Europe for the following half-century.
Key people: Joachim von Ribbentrop, Vyacheslav Molotov, Joseph Stalin