1954 Notable Deaths April 21

Emil Leon Post, Polish-American mathematician and logician (born 1897)

Name: Emil Leon Post, Polish-American mathematician and logician (born 1897)
Start: 1954

On April 21, in the year 1954, Emil Leon Post, Polish-American mathematician and logician (born 1897). This event is recorded as a Notable Deaths event in the history of April 21, one of 329 recorded events on this date across all of history.

1 notable person is associated with this event, including Emil Leon Post. Learn more below.

Emil Leon Post was an American mathematician and logician. He is best known for his work in the field that eventually became known as computability theory.

Key Facts

This event took place on April 21, 1954 (AD era).
It is categorised as a Notable Deaths event in recorded history.
Referenced in 1 Wikipedia article.
1 notable person is recorded as involved in or associated with this event.
Wikipedia source last updated on 16 March 2026.

On This Date in History 329

Type	Year	Date	Event
Notable Deaths	2025	Apr 21	Pope Francis (born 1936)
Notable Deaths	2024	Apr 21	Terry A
Historical Events	2021	Apr 21	Indonesian Navy submarine KRI Nanggala (402) sinks in the Bali Sea during a military drill, killing all 53 on board
Selected Events	2021	Apr 21	The Indonesian Navy submarine Nanggala imploded and sank in the Bali Sea, resulting in the deaths of all 53 people on bo
Historical Events	2019	Apr 21	Eight bombs explode at churches, hotels, and other locations in Sri Lanka on Easter Sunday, killing at least 269
Notable Deaths	2019	Apr 21	Polly Higgins, Scottish barrister, author and environmental lobbyist (born 1968)
Notable Deaths	2018	Apr 21	Nabi Tajima, Japanese supercentenarian (born 1900)
Notable Deaths	2017	Apr 21	Ugo Ehiogu, English footballer (born 1972)
Notable Deaths	2016	Apr 21	Prince, American singer-songwriter, guitarist, producer, and actor (born 1958)
Historical Events	2014	Apr 21	The American city of Flint, Michigan switches its water source to the Flint River, beginning the ongoing Flint water cri
Notable Deaths	2014	Apr 21	George H
Notable Deaths	2014	Apr 21	Win Tin, Burmese journalist and politician, co-founded the National League for Democracy (born 1930)
Selected Events	2014	Apr 21	The city of Flint, Michigan, U
Notable Deaths	2013	Apr 21	Shakuntala Devi, Indian mathematician and astrologer (born 1929)
Notable Deaths	2013	Apr 21	Leopold Engleitner, Austrian Holocaust survivor, author, and educator (born 1905)
Historical Events	2012	Apr 21	Two trains are involved in a head-on collision near Sloterdijk, Amsterdam, in the Netherlands, killing one person and in
Notable Deaths	2012	Apr 21	Doris Betts, American author and academic (born 1932)
Notable Deaths	2011	Apr 21	Catharina Halkes, Dutch theologian and academic (born 1920)
Historical Events	2010	Apr 21	The controversial Kharkiv Pact (Russian Ukrainian Naval Base for Gas Treaty) is signed in Kharkiv, Ukraine, by Ukrainian
Notable Deaths	2010	Apr 21	Gustav Lorentzen, Norwegian singer-songwriter and guitarist (born 1947)
Notable Deaths	2010	Apr 21	Juan Antonio Samaranch, Spanish businessman, seventh President of the International Olympic Committee (born 1920)
Notable Deaths	2010	Apr 21	Kanagaratnam Sriskandan, Sri Lankan-English engineer and civil servant (born 1930)
Selected Events	2010	Apr 21	Ukraine and Russia signed the Kharkiv Pact, extending the Russian lease on naval facilities in Crimea
Notable Births	2008	Apr 21	Hyein, South Korean singer
Notable Births	2007	Apr 21	Princess Isabella of Denmark, daughter of King Frederik X and Queen Mary of Denmark
Notable Deaths	2005	Apr 21	Zhang Chunqiao, Chinese writer and politician, member of the Gang of Four (born 1917)
Historical Events	2004	Apr 21	Five suicide car bombers target police stations in and around Basra, killing 74 people and wounding 160
Notable Births	2003	Apr 21	Xavi Simons, Dutch footballer
Notable Deaths	2003	Apr 21	Nina Simone, American singer-songwriter, pianist, and activist (born 1933)
Notable Births	1999	Apr 21	Choi Hyun-suk, South Korean rapper
Notable Deaths	1999	Apr 21	Buddy Rogers, American actor (born 1904)
Notable Births	1998	Apr 21	Jarrett Allen, American basketball player
Notable Deaths	1998	Apr 21	Jean-François Lyotard, French sociologist and philosopher (born 1924)
Notable Births	1997	Apr 21	Mikel Oyarzabal, Spanish footballer
Notable Deaths	1997	Apr 21	Diosdado Macapagal, Filipino lawyer and politician, 9th President of the Philippines (born 1910)
Historical Events	1996	Apr 21	Four people are killed and 75 are injured in a train accident in Jokela, Finland
Notable Births	1996	Apr 21	Arianne Hartono, Dutch tennis player
Notable Deaths	1996	Apr 21	Abdul Hafeez Kardar, Pakistani cricketer (born 1925)
Notable Deaths	1996	Apr 21	Jimmy Snyder, American sportscaster (born 1919)
Notable Births	1994	Apr 21	Ludwig Augustinsson, Swedish footballer
Historical Events	1993	Apr 21	The Supreme Court in La Paz, Bolivia, sentences former dictator Luis García Meza to 30 years in jail without parole for
Notable Births	1992	Apr 21	Isco, Spanish footballer
Notable Births	1992	Apr 21	Joc Pederson, American baseball player
Notable Deaths	1992	Apr 21	Väinö Linna, Finnish author (born 1920)
Notable Deaths	1991	Apr 21	Willi Boskovsky, Austrian violinist and conductor (born 1909)
Notable Deaths	1990	Apr 21	Erté, Russian-French illustrator (born 1892)
Historical Events	1989	Apr 21	Tiananmen Square protests of 1989: In Beijing, around 100,000 students gather in Tiananmen Square to commemorate Chinese
Notable Births	1989	Apr 21	Nikki Cross, Scottish wrestler
Notable Births	1988	Apr 21	Ricky Berens, American swimmer
Notable Births	1988	Apr 21	Jencarlos Canela, American singer-songwriter and actor