- 1122 Concordat of Worms agreed between Pope Calixtus II and Holy Roman Emperor Henry V
- 1821 Fall of Tripolitsa, Greek forces massacre 30,000 Turks during Greek War of Independence
- 1884 American Herman Hollerith patents his mechanical tabulating machine, the beginning of data processing
- 1889 Nintendo Koppai (Later Nintendo Company, Limited) founded by Fusajiro Yamauchi to produce and market the playing card game Hanafuda.
- 1942 The 'Manhattan Project' commences, under the direction of US General Leslie Groves: its aim - to deliver an atomic bomb
Time capsule, to be opened in 6939, buried at World's Fair in NYC (capsule contained a woman's hat, man's pipe & 1,100' of microfilm)
On September 23, 1938