In 1939, pursuant to the Molotov-Ribbentrop Pact, the USSR and Nazi Germany divided a part of Eastern Europe, specifically greater Poland. As a result, Western Ukrainian lands formerly under Polish colonial rule were overrun by the Soviets. While Polish rule in western Ukraine during the previous 20 years had been onerous to say the least, the Soviets introduced a new level of terror with summary executions, arrests and deportations to Siberia. The Germans entered Ukrainian territory in 1941 showcasing their own brand of repression. However, when Germany began losing the war, the Soviets came back into western Ukraine in 1943. The population of western Ukraine at this point was well aware what to expect from their earlier persecutors. Many began to flee towards Western Europe.