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.

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 Lagoda to the Soviet Union. They also cede the small Finnish coastline on the Arctic Sea.