April 30 » J. J. Thomson of the Cavendish Laboratory announces his discovery of the electron as a subatomic particle, over 1,800 times smaller than a proton (in the atomic nucleus), at a lecture at the Royal Institution in London.
May 26 » Dracula, a Gothic horror novel by Irish author Bram Stoker, is published.
June 22 » British colonial officers Charles Walter Rand and Lt. Charles Egerton Ayerst are assassinated in Pune, Maharashtra, India by the Chapekar brothers and Mahadeo Vinayak Ranade, who are later caught and hanged.
July 2 » British-Italian engineer Guglielmo Marconi obtains a patent for radio in London.
August 10 » German chemist Felix Hoffmann discovers an improved way of synthesizing acetylsalicylic acid (aspirin).
December 6 » London becomes the world's first city to host licensed taxicabs.
Day of marriage August 6, 1921
The temperature on August 6, 1921 was between 15.7 °C and 21.7 °C and averaged 17.7 °C. There was 2.2 mm of rain. There was 5.6 hours of sunshine (37%). The average windspeed was 4 Bft (moderate breeze) and was prevailing from the west-southwest. Source: KNMI
In The Netherlands , there was from September 9, 1918 to September 18, 1922 the cabinet Ruys de Beerenbrouck I, with Jonkheer mr. Ch.J.M. Ruys de Beerenbrouck (RKSP) as prime minister.
February 12 » Bolsheviks launch a revolt in Georgia as a preliminary to the Red Army invasion of Georgia.
February 15 » Kingdom of Romania establishes its legation in Helsinki.
May 3 » West Virginia becomes the first state to legislate a broad sales tax, but does not implement it until a number of years later due to enforcement issues.
September 21 » A storage silo in Oppau, Germany, explodes, killing 500–600 people.
October 29 » United States: Second trial of Sacco and Vanzetti in Boston, Massachusetts.
November 4 » Japanese Prime Minister Hara Takashi is assassinated in Tokyo.
Day of death May 15, 1970
The temperature on May 15, 1970 was between 8.2 °C and 19.9 °C and averaged 13.3 °C. There was 0.8 mm of rain during 1.5 hours. There was 1.3 hours of sunshine (8%). The heavily clouded was. The average windspeed was 2 Bft (weak wind) and was prevailing from the east-northeast. Source: KNMI
April 29 » Vietnam War: United States and South Vietnamese forces invade Cambodia to hunt Viet Cong.
August 24 » Vietnam War protesters bomb Sterling Hall at the University of Wisconsin–Madison, leading to an international manhunt for the perpetrators.
September 4 » Salvador Allende is elected President of Chile.
September 16 » King Hussein of Jordan declares war against the Palestine Liberation Organization, the conflict which became to be known as Black September.
October 2 » An aircraft carrying the Wichita State University football team, administrators, and supporters crashes in Colorado, killing 31 people.
December 23 » The Democratic Republic of the Congo officially becomes a one-party state.
When copying data from this family tree, please include a reference to the origin: Peeters Mathieu, "FutureHistory", database, Genealogy Online (https://www.genealogieonline.nl/stamboom-riske/I6111.php : accessed December 25, 2025), "Theophiel "Theophile" (Theophiel "Theophile") de Groep (1897-1970)".
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