WHAT ALL HAPPENED JULY TO SEPTEMBER 1939
Find out what all happened July to September 1939

General Władysław Sikorski becomes commander-in-chief of the Polish Government in exile. (30. September 1939)

Switzerland mobilizes its forces and the Swiss Parliament elects Henri Guisan to head the Swiss Army (an event that can happen only during war or mobilization). (1. September 1939)

World War II: Germany and the Soviet Union sign a non-aggression treaty, the Molotov-Ribbentrop Pact. In a secret addition to the pact, the Baltic states, Finland, Romania, and Poland are divided between the two nations. (23. August 1939)

First flight of the turbojet-powered Heinkel He 178, the world's first jet aircraft. (27. August 1939)

Holocaust: the last remaining Jewish enterprises in Germany are closed. (6. July 1939)

World War II: The Battle of Barking Creek. (6. September 1939)

Nazi Germany mounts a staged attack on the Gleiwitz radio station, creating an excuse to attack Poland the following day thus starting World War II in Europe. (31. August 1939)

Nazi Germany and the Soviet Union agree on a division of Poland after their invasion during World War II. (28. September 1939)

World War II: France, the United Kingdom, New Zealand and Australia declare war on Germany after the invasion of Poland, forming the Allies. (3. September 1939)

World War II: The Soviet Union joins Nazi Germany's invasion of Poland during the Polish Defensive War of 1939. (17. September 1939)

Romanian Prime Minister Armand Călinescu is assassinated by far-right legionnaires of the fascist paramilitary organization called the Iron Guard. (21. September 1939)

The Nazi propaganda broadcaster known as Lord Haw-Haw begins transmitting. (18. September 1939)

Huỳnh Phú Sổ founds Hòa Hảo Buddhism. (4. July 1939)

World War II: The submarine HMS Oxley is mistakenly sunk by the submarine HMS Triton near Norway and becomes the Royal Navy's first loss. (10. September 1939)

The United Kingdom and Poland form a military alliance in which the UK promises to defend Poland in case of invasion by a foreign power. (25. August 1939)

World War II: Nazi Germany and Slovakia invade Poland, beginning the European phase of World War II. (1. September 1939)

World War II: The United Kingdom and France begin a naval blockade of Germany that lasts until the end of the war. This also marks the beginning of the Battle of the Atlantic. (3. September 1939)

World War II: The Battle of Hel begins, the longest-defended pocket of Polish Army resistance during the German invasion of Poland. (9. September 1939)

World War II: Polish government of Ignacy Mościcki flees to Romania. (18. September 1939)

Lou Gehrig, recently diagnosed with Amyotrophic lateral sclerosis, informs a crowd at Yankee Stadium that he considered himself "The luckiest man on the face of the earth", then announces his retirement from major league baseball. (4. July 1939)