21 September History
- 454 - In Italy, Aetius, the supreme army commander, is murdered in Ravenna by Valentinian III, the emperor of the West.
- 1327 - Edward II of England is murdered by order of his wife.
- 1520 - Suleiman (the Magnificent), son of Selim, becomes Ottoman sultan in Constantinople.
- 1589 - The Duke of Mayenne of France is defeated by Henry IV at the Battle of Arques.
- 1673 - James Needham returns to Virginia after exploring the land to the west, which would become Tennessee.
- 1745 - A Scottish Jacobite army commanded by Lord George Murray routs the Royalist army of General Sir John Cope at Prestonpans.
- 1863 - Union troops defeated at Chickamauga seek refuge in Chattanooga, Tennessee, which is then besieged by Confederate troops.
- 1904 - Exiled Nez Perce leader Chief Joseph dies of a "broken heart".
- 1915 - Stonehenge is sold by auction for 6,600 pounds sterling ($11,500) to a Mr. Chubb, who buys it as a present for his wife. He presents it to the British nation three years later.
- 1929 - Fighting between China and the Soviet Union breaks out along the Manchurian border.
- 1936 - The German army holds its largest maneuvers since 1914.
- 1937 - The women's airspeed record is set at 292 mph by American pilot Jacqueline Cochran.
- 1941 - The German Army cuts off the Crimean Peninsula from the rest of the Soviet Union.
- 1942 - British forces attack the Japanese in Burma.
- 1944 - U.S. troops of the 7th Army, invading Southern France, cross the Meuse River.
- 1978 - Two Soviet cosmonauts set a space endurance record after 96 days in space.
- 1989 - General Colin Powell is confirmed by the U.S. Senate as Chairman of the Joint Chiefs of Staff.
21 September Birthdays
- 1756 - John Loudon McAdam, engineer who invented and gave his name to macadamized roads.
- 1866 - Charles Jean Henri Nicolle, bacteriologist, discovered that typhus fever is transmitted by body louse.
- 1866 - H.G. Wells, science fiction writer whose works include The Time Machine, The Invisible Man and The War of the Worlds.
- 1895 - Juan de la Cierva, aeronautical engineer who invented the autogyro.
- 1902 - Allen Lake, founded Penguin Books in 1935.
- 1912 - Chuck Jones, animator and director of Warner Brothers cartoons.
- 1947 - Stephen King, author best known for supernatural and horror tales.
- 1947 - Marsha Norman, playwright (Getting Out, 'Night Mother).