April 21
Events
Pre-1600
- 753 BC - Romulus founds Rome.
- 43 BC - Battle of Mutina: Mark Antony is again defeated in battle by Aulus Hirtius, who is killed. Antony fails to capture Mutina and Decimus Brutus is murdered shortly after.
- 900 - The Laguna Copperplate Inscription : the Commander-in-Chief of the Kingdom of Tondo, as represented by the Honourable Jayadewa, Lord Minister of Pailah, pardons from all debt the Honourable Namwaran and his relations.
- 1092 - The Diocese of Pisa is elevated to the rank of metropolitan archdiocese by Pope Urban II
- 1506 - The three-day Lisbon Massacre comes to an end with the slaughter of over 1,900 suspected Jews by Portuguese Catholics.
- 1509 - Henry VIII ascends the throne of England on the death of his father, Henry VII.
- 1526 - The last ruler of the Lodi dynasty, Ibrahim Lodi is defeated and killed by Babur in the First Battle of Panipat.
1601–1900
- 1615 - The Wignacourt Aqueduct is inaugurated in Malta.
- 1782 - The city of Rattanakosin, now known internationally as Bangkok, is founded on the eastern bank of the Chao Phraya River by King Buddha Yodfa Chulaloke.
- 1789 - John Adams sworn in as first US Vice President.
- 1789 - George Washington's reception at Trenton is hosted by the Ladies of Trenton as he journeys to New York City for his first inauguration.
- 1792 - Tiradentes, a revolutionary leading a movement for Brazil's independence, is hanged, drawn and quartered.
- 1796 - War of the First Coalition: In the climax of the Montenotte Campaign, Napoleon Bonaparte decisively defeats the army of Piedmont at the Battle of Mondovi, leading to Piedmont's surrender a week later and decisively turning the Italian campaign in France's favor.
- 1802 - Twelve thousand Wahhabis sack Karbala, killing over three thousand inhabitants.
- 1806 - Action of 21 April 1806: A French frigate escapes British forces off the coast of South Africa.
- 1809 - Two Austrian army corps are driven from Landshut by a First French Empire army led by Napoleon as two French corps to the north hold off the main Austrian army on the first day of the Battle of Eckmühl.
- 1821 - Benderli Ali Pasha arrives in Constantinople as the new Grand Vizier of the Ottoman Empire; he remains in power for only nine days before being sent into exile.
- 1836 - Texas Revolution: The Battle of San Jacinto: Republic of Texas forces under Sam Houston defeat troops under Mexican General Antonio López de Santa Anna.
- 1856 - Australian labour movement: Stonemasons and building workers on building sites around Melbourne march from the University of Melbourne to Parliament House to achieve an eight-hour day.
- 1894 - Norway formally adopts the Krag–Jørgensen bolt-action rifle as the main arm of its armed forces, a weapon that would remain in service for almost 50 years.
- 1898 - Spanish–American War: The United States Navy begins a blockade of Cuban ports. When the U.S. Congress issued a declaration of war on April 25, it declared that a state of war had existed from this date.
1901–present
- 1914 - Ypiranga incident: A German arms shipment to Mexico is intercepted by the U.S. Navy near Veracruz.
- 1918 - World War I: German fighter ace Manfred von Richthofen, better known as "The Red Baron", is shot down and killed over Vaux-sur-Somme in France.
- 1926 - Al-Baqi cemetery, former site of the mausoleum of four Shi'a Imams, is leveled to the ground by Wahhabis.
- 1934 - The "Surgeon's Photograph", the most famous photo allegedly showing the Loch Ness Monster, is published in the Daily Mail.
- 1945 - World War II: Soviet forces south of Berlin at Zossen attack the German High Command headquarters.
- 1946 - The U.S. Weather Bureau records that a tornado which struck Timber Lake, South Dakota was, among the widest tornadoes on record.
- 1948 - United Nations Security Council Resolution 47 relating to Kashmir conflict is adopted.
- 1950 - The Nainital wedding massacre occurs, killing 22 members of the Harijan caste.
- 1952 - Secretary's Day is first celebrated.
- 1958 - United Air Lines Flight 736 collides with a United States Air Force fighter jet near Arden, Nevada in what is now Enterprise, Nevada.
- 1960 - Brasília, Brazil's capital, is officially inaugurated. At 09:30, the Three Powers of the Republic are simultaneously transferred from the old capital, Rio de Janeiro.
- 1962 - The Seattle World's Fair opens. It is the first World's Fair in the United States since World War II.
- 1963 - The first election of the Universal House of Justice is held, marking its establishment as the supreme governing institution of the Baháʼí Faith.
- 1964 - A Transit-5bn satellite fails to reach orbit after launch; as it re-enters the atmosphere, of radioactive plutonium in its SNAP RTG power source is widely dispersed.
- 1965 - The 1964–1965 New York World's Fair opens for its second and final season.
- 1966 - Rastafari movement: Haile Selassie of Ethiopia visits Jamaica, an event now celebrated as Grounation Day.
- 1967 - A few days before the general election in Greece, Colonel George Papadopoulos leads a coup d'état, establishing a military regime that lasts for seven years.
- 1967 - A tornado outbreak in Illinois, United States, kills over 50 and injures over 1000. Belvidere sustains over 500 casualties as a violent tornado strikes the high school. Another tornado near Chicago causes another 500 casualties, devastating Oak Lawn.
- 1972 - Astronauts John Young and Charles Duke fly Apollo 16's Apollo Lunar Module to the Moon's surface, the fifth NASA Apollo Program crewed lunar landing.
- 1975 - Vietnam War: President of South Vietnam Nguyễn Văn Thiệu flees Saigon, as Xuân Lộc, the last South Vietnamese outpost blocking a direct North Vietnamese assault on Saigon, falls.
- 1977 - Annie opens on Broadway.
- 1982 - Baseball: Rollie Fingers of the Milwaukee Brewers becomes the first pitcher to record 300 saves.
- 1985 - The compound of the militant group The Covenant, The Sword, and the Arm of the Lord surrenders to federal authorities in Arkansas after a two-day government siege.
- 1987 - The Tamil Tigers are blamed for a car bomb that detonates in the Sri Lankan capital city of Colombo, killing 106 people.
- 1989 - Tiananmen Square protests of 1989: In Beijing, around 100,000 students gather in Tiananmen Square to commemorate Chinese reform leader Hu Yaobang.
- 1993 - The Supreme Court in La Paz, Bolivia, sentences former dictator Luis García Meza to 30 years in jail without parole for murder, theft, fraud and violating the constitution.
- 2004 - Five suicide car bombers target police stations in and around Basra, killing 74 people and wounding 160.
- 2010 - The controversial Kharkiv Pact is signed in Kharkiv, Ukraine, by Ukrainian president Viktor Yanukovych and Russian president Dmitry Medvedev; it was unilaterally terminated by Russia on March 31, 2014.
- 2012 - Two trains are involved in a head-on collision near Sloterdijk, Amsterdam, in the Netherlands, killing one person and injuring 116 others.
- 2014 - The American city of Flint, Michigan switches its water source to the Flint River, beginning the ongoing Flint water crisis which has caused lead poisoning in up to 12,000 people, and at least 12 deaths from Legionnaires' disease, ultimately leading to criminal indictments against 15 people, five of whom have been charged with involuntary manslaughter.
- 2019 - Eight bombs explode at churches, hotels, and other locations in Sri Lanka on Easter Sunday, killing at least 269.
- 2021 - Indonesian Navy submarine KRI Nanggala sinks in the Bali Sea during a military drill, killing all 53 on board.
Births
Pre-1600
- 1132 - Sancho VI, king of Navarre
- 1488 - Ulrich von Hutten, German religious reformer
- 1523 - Marco Antonio Bragadin, Venetian lawyer and military officer
- 1555 - Ludovico Carracci, Italian painter and etcher
1601–1900
- 1619 - Jan van Riebeeck, Dutch founder of Cape Town
- 1630 - Pieter Gerritsz van Roestraten, Dutch-English painter
- 1631 - Francesco Maidalchini, Catholic cardinal
- 1642 - Simon de la Loubère, French mathematician, poet, and diplomat
- 1651 - Joseph Vaz, Sri Lankan priest, missionary, and saint
- 1652 - Michel Rolle, French mathematician and academic
- 1671 - John Law, Scottish economist
- 1673 - Wilhelmine Amalia of Brunswick-Lüneburg
- 1713 - Louis de Noailles, French general
- 1730 - Antonín Kammel, Czech violinist and composer
- 1752 - Pierre-Alexandre-Laurent Forfait, French engineer, hydrographer, and politician, French Minister of Marine and the Colonies
- 1752 - Humphry Repton, English gardener and author
- 1774 - Jean-Baptiste Biot, French physicist, astronomer, and mathematician
- 1775 - Alexander Anderson, Scottish-American illustrator and engraver
- 1783 - Reginald Heber, English priest
- 1790 - Manuel Blanco Encalada, Spanish-Chilean admiral and politician, 1st President of Chile
- 1810 - John Putnam Chapin, American politician, 10th Mayor of Chicago
- 1811 - Alson Sherman, American merchant and politician, 8th Mayor of Chicago
- 1814 - Angela Burdett-Coutts, 1st Baroness Burdett-Coutts, English art collector and philanthropist
- 1816 - Charlotte Brontë, English novelist and poet
- 1837 - Fredrik Bajer, Danish lieutenant and politician, Nobel Prize laureate
- 1838 - John Muir, Scottish-American environmentalist and author
- 1854 - William Stang, German-American bishop
- 1864 - Max Weber, German economist and sociologist
- 1868 - Alfred Henry Maurer, American painter
- 1868 - Mary Rogers Miller, American author and educator
- 1870 - Edwin Stanton Porter, American director, producer, and screenwriter
- 1874 - Vincent Scotto, French composer and actor
- 1882 - Percy Williams Bridgman, American physicist and academic, Nobel Prize laureate
- 1885 - Tatu Kolehmainen, Finnish runner
- 1887 - Joe McCarthy, American baseball manager
- 1889 - Marcel Boussac, French businessman
- 1889 - Paul Karrer, Russian-Swiss chemist and academic, Nobel Prize laureate
- 1889 - Efrem Zimbalist, Sr., Russian-American violinist, composer, and conductor
- 1892 - Freddie Dixon, English motorcycle racer and racing driver
- 1893 - Romeo Bertini, Italian runner
- 1897 - Odd Lindbäck-Larsen, Norwegian Army general and war historian
- 1898 - Maurice Wilson, English soldier, pilot, and mountaineer
- 1899 - Randall Thompson, American composer and academic