1939 March 14–15, 1939 Under German pressure, the Slovaks declare their independence and form a Slovak Republic. The Germans occupy the dismantled Czech lands in violation of the Munich agreement and form the Protectorate of Bohemia and Moravia. March 31, 1939 France and Great Britain guarantee the integrity of the borders of the Polish state. April 7–15, 1939 Fascist Italy invades and annexes Albania. August 23, 1939 Nazi Germany and the Soviet Union sign a non-aggression agreement and a secret protocol dividing eastern Europe into spheres of influence. September 1, 1939 Germany invades Poland, initiating World War II in Europe. September 3, 1939 Honoring their guarantee of Poland’s borders, Great Britain and France declare war on Germany. September 17, 1939 The Soviet Union invades Poland from the east. The Polish government flees into exile via Romania, first to France and then later to Great Britain. September 27–29, 1939 Warsaw surrenders on September 27. Germany and the Soviet Union divide Poland between them. Source: 1940 November 30, 1939–March 12, 1940 The Soviet Union invades Finland, initiating the so-called Winter War. The Finns sue for an armistice and cede the northern shores of Lake Ladoga to the Soviet Union. They also cede the small Finnish coastline on the Arctic Ocean. April 9, 1940–June 9, 1940 Germany invades Denmark and Norway. Denmark surrenders on the day of the attack. Norway holds out until June 9. May 10, 1940–June 22, 1940 Germany attacks western Europe, specifically France and the neutral Low Countries (Belgium, the Netherlands, and Luxembourg). Luxembourg is occupied on May 10; the Netherlands surrenders on May 14; and Belgium surrenders on May 28. On June 22, France signs an armistice agreement by which the Germans occupy the northern half of the country and the entire Atlantic coastline. In southern France, a collaborationist regime with its capital in Vichy is established. June 10, 1940 Italy enters the war. Italy invades southern France on June 21. June 28, 1940 The Soviet Union forces Romania to cede the eastern province of Bessarabia and the northern half of Bukovina to Soviet Ukraine. June 14, 1940–August 6, 1940 The Soviet Union occupies the Baltic states (Estonia, Latvia, and Lithuania) on June 14–18. On July 14–15, it engineers Communist coup d’états in each of these countries and then annexes them as Soviet Republics on August 3–6. July 10, 1940–October 31, 1940 The air war known as the Battle