43 a. C.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.
900The Laguna Copperplate Inscription (the earliest known written document found in what is now the Philippines): 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.
1092The Diocese of Pisa is elevated to the rank of metropolitan archdiocese by Pope Urban II.
1506The three-day Lisbon Massacre comes to an end with the slaughter of over 1,900 suspected Jews by Portuguese Catholics.
1509Henry VIII ascends the throne of England on the death of his father, Henry VII.
1526The last ruler of the Lodi dynasty, Ibrahim Lodi, is defeated and killed by Babur in the First Battle of Panipat.
1615The Wignacourt Aqueduct is inaugurated in Malta.
1782The city of Rattanakosin, now known internationally as Bangkok, is founded on the eastern bank of the Chao Phraya River by King Buddha Yodfa Chulaloke.
1789George Washington's reception at Trenton is hosted by the Ladies of Trenton as he journeys to New York City for his first inauguration.
1792Tiradentes, a revolutionary leading a movement for Brazil's independence, is hanged, drawn and quartered.
1796War 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.
1802Twelve thousand Wahhabis sack Karbala, killing over three thousand inhabitants.
1806Action of 21 April 1806: A French frigate escapes British forces off the coast of South Africa.
1809Two 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.
1821Benderli 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.
1856Australian 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.
1894Norway 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.
1898Spanish–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.
1914Ypiranga incident: A German arms shipment to Mexico is intercepted by the U.S. Navy near Veracruz.
1926Al-Baqi cemetery, former site of the mausoleum of four Shi'a Imams, is leveled to the ground by Wahhabis.
1934The "Surgeon's Photograph", the most famous photo allegedly showing the Loch Ness Monster, is published in the Daily Mail (in 1994, it is revealed to be a hoax).
1945World War II: Soviet forces south of Berlin at Zossen attack the German High Command headquarters.
1946The U.S. Weather Bureau records that a tornado which struck Timber Lake, South Dakota was , among the widest tornadoes on record.
1948United Nations Security Council Resolution 47 relating to Kashmir conflict is adopted.
1950The Nainital wedding massacre occurs, killing 22 members of the Harijan caste.
1952Secretary's Day (now Administrative Professionals' Day) is first celebrated.
1958United Air Lines Flight 736 collides with a United States Air Force fighter jet near Arden, Nevada in what is now Enterprise, Nevada.
1960Brasília, 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.
1962The Seattle World's Fair (Century 21 Exposition) opens. It is the first World's Fair in the United States since World War II.
1963The first election of the Universal House of Justice is held, marking its establishment as the supreme governing institution of the Baháʼí Faith.
1964A 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.
1965The 1964–1965 New York World's Fair opens for its second and final season.
1967A tornado outbreak in Illinois, United States, kills over 50 and injures over 1,000. Belvidere sustains over 500 casualties as a violent tornado strikes the high school. Another tornado near Chicago causes another 500 casualties, devastating Oak Lawn.
1972Astronauts 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.
1982Baseball: Rollie Fingers of the Milwaukee Brewers becomes the first pitcher to record 300 saves.
1985The 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.
1987The Tamil Tigers are blamed for a car bomb that detonates in the Sri Lankan capital city of Colombo, killing 106 people.
1993The 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.
1996Four people are killed and 75 are injured in a train accident in Jokela, Finland.
2004Five suicide car bombers target police stations in and around Basra, killing 74 people and wounding 160.
2010The controversial Kharkiv Pact (Russian Ukrainian Naval Base for Gas Treaty) 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.
2012Two trains are involved in a head-on collision near Sloterdijk, Amsterdam, in the Netherlands, killing one person and injuring 116 others.
2019Eight bombs explode at churches, hotels, and other locations in Sri Lanka on Easter Sunday, killing at least 269.
2021Indonesian Navy submarine KRI Nanggala (402) sinks in the Bali Sea during a military drill, killing all 53 on board.
Nacimientos (164)
1132Sancho VI, king of Navarre (died 1194)
1488Ulrich von Hutten, German religious reformer (died 1523)
1523Marco Antonio Bragadin, Venetian lawyer and military officer (died 1571)
1555Ludovico Carracci, Italian painter and etcher (died 1619)
1619Jan van Riebeeck, Dutch founder of Cape Town (died 1677)
1630Pieter Gerritsz van Roestraten, Dutch-English painter (died 1700)