On this day: August 21

Events on August 21

• 1415 Henry the Navigator leads Portuguese forces to victory over the Marinids at the Conquest of Ceuta. Wikipedia
• 1680 Pueblo Indians capture Santa Fe from the Spanish during the Pueblo Revolt. Wikipedia
• 1689 Jacobite clans clashed with a regiment of Covenanters in the streets of Dunkeld, Scotland. Wikipedia
• 1716 Seventh Ottoman–Venetian War: Ottoman forces suddenly abandoned their siege of Corfu, allowing the Republic of Venice to preserve its rule over the Ionian Islands. Wikipedia
• 1717 Austro-Turkish War: Austrian troops under Prince Eugene of Savoy captured the strategically important city of Belgrade from the Ottoman Empire. Wikipedia
• 1772 King Gustav III completes his coup d'état by adopting a new Constitution, ending half a century of parliamentary rule in Sweden and installing himself as an enlightened despot. Wikipedia
• 1789 The national colours of Italy first appeared on a tricolour cockade in Genoa. Wikipedia
• 1791 Enslaved Africans in Saint-Domingue, led by Dutty Boukman, held a Vodou ceremony that became a pivotal act of resistance. This gathering sparked a mass uprising against slavery, marking the beginning of the Haitian Revolution. Wikipedia
• 1808 Peninsular War: British and Portuguese forces put an end to the first French invasion of Portugal at the Battle of Vimeiro. Wikipedia
• 1911 Leonardo da Vinci's Mona Lisa was stolen from the Louvre by museum employee Vincenzo Peruggia and was not recovered until two years later. Wikipedia
• 1942 World War II: The Imperial Japanese Army lost the Battle of the Tenaru, the first of its three major land offensives during the Guadalcanal campaign. Wikipedia
• 1944 World War II: A combined Canadian–Polish force captured the town of Falaise, France, in the final offensive of the Battle of Normandy. Wikipedia
• 1944 Dumbarton Oaks Conference, prelude to the United Nations, begins. Wikipedia
• 1945 American physicist Harry Daghlian accidentally dropped a tungsten carbide brick onto a plutonium bomb core, exposing himself to neutron radiation and later becoming the first Manhattan Project fatality due to a criticality accident. Wikipedia
• 1957 The Soviet Union successfully conducts a long-range test flight of the R-7 Semyorka, the first intercontinental ballistic missile. Wikipedia
• 1963 South Vietnamese special forces loyal to Ngô Đình Nhu, the brother of President Ngô Đình Diệm, raided and vandalised Buddhist pagodas across the country, arresting thousands and leaving hundreds dead. Wikipedia
• 1968 Cold War: Nicolae Ceaușescu, leader of the Socialist Republic of Romania, publicly condemns the Soviet-led Warsaw Pact invasion of Czechoslovakia, encouraging the Romanian population to arm itself against possible Soviet reprisals. Wikipedia
• 1971 Six people were killed during an escape attempt and riot at San Quentin State Prison in California; the subsequent trial of six inmates was the longest in state history at the time. Wikipedia
• 1983 Philippine opposition leader Benigno Aquino Jr. is assassinated at Manila International Airport (now renamed Ninoy Aquino International Airport in his honor). Wikipedia
• 1986 A limnic eruption of Lake Nyos in Cameroon released a cloud of carbon dioxide, suffocating 1,746 people and 3,500 livestock. Wikipedia
• 1991 Coup attempt against Mikhail Gorbachev collapses. Wikipedia
• 1993 NASA loses contact with the Mars Observer spacecraft. Wikipedia
• 2007 BioShock was released in North America, becoming a critical success and a demonstration of video games as an art form. Wikipedia
• 2013 Syrian civil war: Areas controlled by the Syrian opposition in Ghouta, Damascus, were attacked by rockets containing sarin, killing at least 281 people. Wikipedia
• 2015 Passengers on a Thalys train from Amsterdam to Paris confronted and subdued an attacker who attempted a mass shooting. Wikipedia
• 2017 A solar eclipse traverses the continental United States. Wikipedia

Born on August 21

• 1165 Philip II of France (died 1223) Wikipedia
• 1567 Francis de Sales, Swiss bishop and saint (died 1622) Wikipedia
• 1765 William IV, King of the United Kingdom (died 1837) Wikipedia
• 1789 Augustin-Louis Cauchy, French mathematician and academic (died 1857) Wikipedia
• 1798 Jules Michelet, French historian and philosopher (died 1874) Wikipedia
• 1904 Count Basie, American pianist, composer, and bandleader (died 1984) Wikipedia
• 1917 Leonid Hurwicz, Polish-American economist and mathematician (died 2008) Wikipedia
• 1930 Princess Margaret, Countess of Snowdon (died 2002) Wikipedia
• 1936 Wilt Chamberlain, American basketball player and coach (died 1999) Wikipedia
• 1938 Kenny Rogers, American singer-songwriter, guitarist, producer, and actor (died 2020) Wikipedia
• 1939 Festus Mogae, Botswana economist and politician, third President of Botswana (died 2026) Wikipedia
• 1956 Kim Cattrall, English-Canadian actress Wikipedia
• 1961 Stephen Hillenburg, American marine biologist, cartoonist, animator and creator of SpongeBob SquarePants (died 2018) Wikipedia
• 1963 Mohammed VI of Morocco, King of Morocco Wikipedia
• 1967 Serj Tankian, Lebanese-born Armenian-American singer-songwriter, multi-instrumentalist, and record producer Wikipedia
• 1967 Carrie-Anne Moss, Canadian actress Wikipedia
• 1973 Sergey Brin, Russian-American computer scientist and businessman, co-founded Google Wikipedia
• 1984 Alizée, French singer Wikipedia
• 1986 Usain Bolt, Jamaican sprinter Wikipedia
• 1986 Paetongtarn Shinawatra, Thai politician and 31st Prime Minister of Thailand Wikipedia
• 1988 Robert Lewandowski, Polish footballer Wikipedia
• 1989 Hayden Panettiere, American actress (died 2026) Wikipedia

Died on August 21

• 1131 King Baldwin II of Jerusalem Wikipedia
• 1568 Jean Parisot de Valette, 49th Grandmaster of the Knights Hospitaller (born 1495) Wikipedia
• 1614 Elizabeth Báthory, Hungarian countess and purported serial killer (born 1560) Wikipedia
• 1762 Lady Mary Wortley Montagu, English author, poet, and playwright (born 1689) Wikipedia
• 1814 Benjamin Thompson, American-English physicist and colonel (born 1753) Wikipedia
• 1838 Adelbert von Chamisso, German botanist and poet (born 1781) Wikipedia
• 1940 Leon Trotsky, Russian theorist and politician, founded the Red Army (born 1879) Wikipedia
• 1943 Henrik Pontoppidan, Danish journalist and author, Nobel Prize laureate (born 1857) Wikipedia
• 1964 Palmiro Togliatti, Italian journalist and politician, Italian Minister of Justice (born 1893) Wikipedia
• 1979 Giuseppe Meazza, Italian footballer and manager (born 1910) Wikipedia
• 1983 Benigno Aquino Jr., Filipino journalist and politician (born 1932) Wikipedia
• 1995 Subrahmanyan Chandrasekhar, Indian-American astrophysicist and mathematician, Nobel Prize laureate (born 1910) Wikipedia
• 2005 Robert Moog, American businessman, founded Moog Music (born 1934) Wikipedia
• 2018 Stefán Karl Stefánsson, Icelandic actor and singer (born 1975) Wikipedia

Holidays and observances

• Christian Feast Day: Abraham of Smolensk (Eastern Orthodox Church) Wikipedia
• Christian Feast Day: Bernard of Alzira Wikipedia
• Christian Feast Day: Cyriaca Wikipedia
• Christian Feast Day: Euprepius of Verona Wikipedia
• Christian Feast Day: Maximilian of Antioch Wikipedia
• Christian Feast Day: Our Lady of Knock Wikipedia
• Christian Feast Day: Pope Pius X Wikipedia
• Christian Feast Day: Sidonius Apollinaris Wikipedia
• Christian Feast Day: Blessed Victoire Rasoamanarivo Wikipedia
• Christian Feast Day: August 21 (Eastern Orthodox liturgics) Wikipedia
• Ninoy Aquino Day (Philippines) Wikipedia
• Youth Day (Morocco) Wikipedia
• World Senior Citizen's Day Wikipedia

Sources

• Wikipedia — “August 21” — events, births, deaths and observances (text under CC BY-SA 4.0) (checked 2026-10-15)
• Wikipedia — “Selected anniversaries/August 21” — the anniversaries editors chose for the date and the article each one is about (checked 2026-10-15)
• Wikidata — in how many language editions each entry's own article exists, used to fill the lists (CC0) (checked 2026-10-15)
• vacanza/holidays (open-source holiday rules, MIT licence) — holiday rules used to build the lists (checked 2026-10-15)

The events, births, deaths and observances above are from the English Wikipedia article “August 21” and the articles it links to (authors and history), retrieved 2026-10-15 through the Wikimedia “On this day” feed. They are licensed under CC BY-SA 4.0; this selection is shared under the same licence. Every anniversary that Wikipedia's editors selected for August 21 stays on the list; the remaining places, up to 26 events, 22 births and 14 deaths, go to the entries whose own article — about the event itself, or else the person or thing it is about — appears in the most language editions (counted from Wikidata); an article about a person or thing, which covers far more than one day, counts half. An entry with no article of its own counts, also at half, by the least covered article it links, and one that links only places counts for nothing. Each list runs by year, and the wording is unchanged apart from removing references to pictures, audio and video.