January 31 » Czechoslav Trade Union Association is founded in Prague.
April 18 » The Greco-Turkish War is declared between Greece and the Ottoman Empire.
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.
June 16 » A treaty annexing the Republic of Hawaii to the United States is signed; the Republic would not be dissolved until a year later.
July 11 » Salomon August Andrée leaves Spitsbergen to attempt to reach the North Pole by balloon. He later crashes and dies.
August 21 » Oldsmobile, an American automobile manufacturer and marque, is founded.
Day of marriage May 12, 1923
The temperature on May 12, 1923 was between 2.7 °C and 11.8 °C and averaged 6.2 °C. There was 8.1 mm of rain. There was 5.9 hours of sunshine (38%). The average windspeed was 4 Bft (moderate breeze) and was prevailing from the southwest. Source: KNMI
In The Netherlands , there was from September 19, 1922 to August 4, 1925 the cabinet Ruys de Beerenbrouck II, with Jonkheer mr. Ch.J.M. Ruys de Beerenbrouck (RKSP) as prime minister.
When copying data from this family tree, please include a reference to the origin: Tjitze Koster, "Family tree Koster Twijslerheide e.o.", database, Genealogy Online (https://www.genealogieonline.nl/stamboom-koster/I1990.php : accessed January 18, 2026), "Pieter Koster (1897-????)".
Copy warning
Genealogical publications are copyright protected. Although data is often retrieved from public archives, the searching, interpreting, collecting, selecting and sorting of the data results in a unique product. Copyright protected work may not simply be copied or republished.
Please stick to the following rules
Request permission to copy data or at least inform the author, chances are that the author gives permission, often the contact also leads to more exchange of data.
Do not use this data until you have checked it, preferably at the source (the archives).
State from whom you have copied the data and ideally also his/her original source.