1st » World War II: Nazi Germany and Slovak Republic (1939–45) Slovakia Invasion of Poland invade Second Polish Republic Poland, beginning the European phase of World War II.
1st » General George C. Marshall becomes Joint Chiefs of Staff e.g Chief of Staff of the United States Army.
1st » The Wound Badge for Wehrmacht, SS, Kriegsmarine, and Luftwaffe soldiers is instituted. The final version of the Iron Cross is also instituted on this date.
1st » 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).
1st » Adolf Hitler signs an order to begin the Action T4 called systematic euthanasia of mentally ill and disabled people.
2nd » World War II: following the start of the Invasion of Poland known as invasion of Second Polish Republic e.g Poland the previous day, the Free City of Danzig (now Gdańsk, Poland) is annexed by Nazi Germany.
3rd » World War II: France, the United Kingdom, New Zealand and Australia declare war on Germany after the invasion of Poland, forming the Allies of World War II known as Allies.
3rd » World War II: The United Kingdom and France begin a Blockade of Germany (1939–45) named naval blockade of Germany that lasts until the end of the war. This also marks the beginning of the Battle of the Atlantic.
4th » World War II: A Bristol Blenheim is the first British aircraft to cross the German coast following the declaration of war and German ships are bombed.
6th » World War II: At the Battle of Barking Creek, Britain suffers its first fighter pilot casualty of the Second World War as a result of friendly fire.
6th » World War II: Union of South Africa named South Africa declares war on Nazi Germany.
9th » World War II: The Battle of Hel begins, the longest-defended pocket of Polish Army resistance during the German invasion of Poland.
10th » World War II: Canada declares war on Nazi Germany, joining the Allies of World War II e.g Allies Poland, France, the United Kingdom, New Zealand and Australia.
14th » World War II: The Estonian military boards the Polish submarine ship ORP Orzeł 1938 6 in Tallinn, sparking a Orzeł incident diplomatic incident that the Soviet Union will later use to justify the annexation of Estonia.
17th » World War II: A German U-boat German submarine U-29 (1936) 'U 29' sinks the British aircraft carrier HMS Courageous 50 6.
17th » Taisto Mäki becomes the first man to run the 10000 metres known as 10,000 metres in under 30 minutes, in a time of 29:52.6
18th » World War II: Second Polish Republic known as Polish government of Ignacy Mościcki flees to Kingdom of Romania e.g Romania.
18th » The Nazi propaganda broadcaster known as Lord Haw-Haw begins transmitting.
19th » World War II: The Battle of Kępa Oksywska concludes, with Polish losses reaching roughly 14% of all the forces engaged.
21st » Romanian Prime Minister Armand Călinescu is assassinated by far-right legionnaires of the fascist paramilitary organization called the Iron Guard.
22nd » Joint victory parade of Wehrmacht and Red Army in Brest, Belarus or Brest-Litovsk at the end of the Invasion of Poland.
28th » Nazi Germany and the Soviet Union German–Soviet Treaty of Friendship, Cooperation and Demarcation named agree on a division of Poland after their invasion during World War II.
28th » Warsaw surrenders to Nazi Germany during World War II.
30th » General Władysław Sikorski becomes commander-in-chief of the Poland named Polish Government in exile.
30th » NBC broadcasts the first televised American football game between the Waynesburg Yellow Jackets and the Fordham Rams. Fordham won the game 34-7.
Famous Birthdays on September in 1939
1st » Lily Tomlin, American actress, producer, and screenwriter
3rd » Vladimir Bakulin, Kazakhstani wrestler (d. 2012)
4th » Denis Lindsay, South African cricketer and referee (d. 2005)
5th » Claudette Colvin, American nurse and activist
5th » George Lazenby, Australian actor
5th » Clay Regazzoni, Swiss race car driver (d. 2006)
5th » John Stewart (musician) named John Stewart, American singer-songwriter and guitarist (The Kingston Trio) (d. 2008)
5th » George Tremlett, English author and politician
6th » Brigid Berlin, American actress, painter, and photographer
6th » Errol Black, Canadian academic and politician (d. 2012)
6th » David Allan Coe, American singer-songwriter and guitarist
6th » Dan Cragg, American soldier and author
6th » Susumu Tonegawa, Japanese biologist and immunologist, Nobel Prize in Physiology or Medicine named Nobel Prize laureate
7th » Latimore (musician) or Latimore, American singer-songwriter and pianist
7th » Peter Gill (playwright) called Peter Gill, Welsh actor, director, and playwright
7th » Bruce Gray, Puerto Rican-Canadian actor
8th » Carsten Keller, German field hockey player and coach
8th » Guitar Shorty, American singer and guitarist