September 1, 1939:  World War II starts when Germany invades Poland by attacking the Free City of Danzig

September 2, 31 BC: Battle of Actium: decisive naval battle that effectively ends the Roman Republic. Octavian's forces defeat those under Mark Antony and Cleopatra off the western coast of Greece.

September 3: 1939: World War II: Britain declares war on Germany after invasion of Poland. France follows 6 hours later quickly joined by Australia, New Zealand, South Africa & Canada

September 4, 476: Romulus Augustulus, last Western Roman Emperor, abdicates after forces led by Odoacer invade Rome. Traditional end of the Western Roman Empire

September 5, 1198:Philips of Zwabia, Prince of Hohenstaufen, crowned King of Germany and King of the Romans

September 6, 1866: Frederick Douglass is 1st US black delegate to a national convention

September 7, 1191: Third Crusade: Battle of Arsuf - Richard I of England defeats Saladin at Arsuf.

September 8, 1522: Spanish navigator Juan de Elcano returns to Spain, completing 1st circumnavigation of the globe (expedition began under Ferdinand Magellan)

September 9, 1945: 1st "bug" in a computer program discovered by Grace Hopper, a moth was removed with tweezers from a relay & taped into the log

September 10, 1882: 1st international conference to promote anti-semitism meets Dresden Germany (Congress for Safeguarding of Non-Jewish Interests)

September 11, 2001: Terrorist attacks from Al Quaeda group in NY. Twin towers fall killing 2996 people

September 12, 1624: 1st submarine publicly tested in London on the Thames for King James I

September 13, 1791: France's King Louis XVI accepts constitution

September 14 1939: World's 1st practical helicopter, the VS-300 designed by Igor Sikorsky takes (tethered) flight in Stratford, Connecticut

September 15, 1928: Scottish bacteriologist Alexander Fleming discovers penicillin while studying influenza