On September 29, 1939, Germany and the Soviet Union agree to divide control of occupied Poland roughly along the Bug River—the Germans taking everything west, the Soviets taking everything east.
As a follow-up to the Molotov-Ribbentrop Pact, (also known as the Hitler-Stalin Pact), that created a non-aggression treaty between the two behemoth military powers of Germany and the U.S.S.R., Joachim von Ribbentrop, the German foreign minister, met with his Soviet counterpart, V.M. Molotov, to sign the German-Soviet Boundary and Friendship Treaty. The fine print of the original non-aggression pact had promised the Soviets a slice of eastern Poland; now it was merely a matter of agreeing where to draw the lines.