January 31 » Czechoslav Trade Union Association is founded in Prague.
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 16 » A treaty annexing the Republic of Hawaii to the United States is signed; the Republic would not be dissolved until a year later.
August 2 » Anglo-Afghan War: The Siege of Malakand ends when a relief column is able to reach the British garrison in the Malakand states.
September 10 » Lattimer massacre: A sheriff's posse kills 19 unarmed striking immigrant miners in Lattimer, Pennsylvania, United States.
Day of marriage April 30, 1921
The temperature on April 30, 1921 was between 6.8 °C and 20.2 °C and averaged 13.7 °C. There was 12.0 hours of sunshine (81%). The average windspeed was 3 Bft (moderate breeze) and was prevailing from the northeast. 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 27 » The International Working Union of Socialist Parties is founded in Vienna.
April 11 » Emir Abdullah establishes the first centralised government in the newly created British protectorate of Transjordan.
June 20 » Workers of Buckingham and Carnatic Mills in the city of Chennai, India, begin a four-month strike.
July 11 » A truce in the Irish War of Independence comes into effect.
September 21 » A storage silo in Oppau, Germany, explodes, killing 500–600 people.
December 6 » The Anglo-Irish Treaty is signed in London by British and Irish representatives.
Day of death September 2, 1980
The temperature on September 2, 1980 was between 7.3 °C and 20.5 °C and averaged 14.1 °C. There was -0.1 mm of rain. There was 10.5 hours of sunshine (77%). The partly clouded was. The average windspeed was 1 Bft (weak wind) and was prevailing from the south-southeast. Source: KNMI
In The Netherlands , there was from Monday, December 19, 1977 to Friday, September 11, 1981 the cabinet Van Agt I, with Mr. A.A.M. van Agt (CDA/KVP) as prime minister.
March 27 » Silver Thursday: A steep fall in silver prices, resulting from the Hunt Brothers attempting to corner the market in silver, leads to panic on commodity and futures exchanges.
April 9 » The Iraqi regime of Saddam Hussein kills philosopher Muhammad Baqir al-Sadr and his sister Bint al-Huda after three days of torture.
May 18 » Mount St. Helens erupts in Washington, United States, killing 57 people and causing $3billion in damage.
July 1 » "O Canada" officially becomes the national anthem of Canada.
August 1 » Vigdís Finnbogadóttir is elected President of Iceland and becomes the world's first democratically elected female head of state.
December 8 » Former Beatle John Lennon is murdered in front of The Dakota in New York City.
When copying data from this family tree, please include a reference to the origin: Hendrik Dreyer, "Dreyer Tree", database, Genealogy Online (https://www.genealogieonline.nl/dreyer-tree/I18762.php : accessed January 28, 2026), "Roelof Jacobus Coertze (1897-1980)".
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