- 1303 – The Sapienza University of Rome is instituted by a bull of Pope Boniface VIII.[1]
- 1453 – Three Genoese galleys and a Byzantine blockade runner fight their way through an Ottoman blockading fleet a few weeks before the fall of Constantinople.
- 1534 – Jacques Cartier begins his first voyage to what is today the east coast of Canada, Newfoundland and Labrador.[2]
- 1535 – The sun dog phenomenon is observed over Stockholm,[3] as later depicted in the famous painting Vädersolstavlan.
- 1653 – Oliver Cromwell dissolves the Rump Parliament.
- 1657 – Admiral Robert Blake destroys a Spanish silver fleet under heavy fire at the Battle of Santa Cruz de Tenerife.
- 1657 – Freedom of religion is granted to the Jews of New Amsterdam (later New York City).
- 1689 – Deposed monarch James II of England lays siege to Derry.
- 1752 – Start of Konbaung–Hanthawaddy War, a new phase in the Burmese Civil War (1740–57).
- 1770 – The Georgian king, Erekle II, abandoned by his Russian ally Count Totleben, wins a victory over Ottoman forces at Aspindza.
- 1775 – American Revolutionary War: The Siege of Boston begins, following the battles at Lexington and Concord.
- 1789 – George Washington arrives at Grays Ferry, Philadelphia while en route to Manhattan for his inauguration.
- 1792 – France declares war against the “King of Hungary and Bohemia“, the beginning of French Revolutionary Wars.
- 1800 – The Septinsular Republic is established.
- 1809 – Two Austrian army corps in Bavaria are defeated by a First French Empire army led by Napoleon at the Battle of Abensberg on the second day of a four-day campaign that ended in a French victory.
- 1810 – The Governor of Caracas, Venezuela declares independence from Spain.
- 1818 – The case of Ashford v Thornton ends, with Abraham Thornton allowed to go free rather than face a retrial for murder, after his demand for trial by battle is upheld.
- 1828 – René Caillié becomes the second non-Muslim to enter (and the first to return from) Timbuktu, following Major Gordon Laing.
- 1836 – U.S. Congress passes an act creating the Wisconsin Territory.
- 1861 – American Civil War: Robert E. Lee resigns his commission in the United States Army in order to command the forces of the state of Virginia.[4]
- 1862 – Louis Pasteur and Claude Bernard complete the experiment disproving the theory of spontaneous generation.
- 1865 – Astronomer Angelo Secchi demonstrates the Secchi disk, which measures water clarity, aboard Pope Pius IX‘s yacht, the L’Immaculata Concezion.
- 1876 – The April Uprising begins. Its suppression shocks European opinion, and Bulgarian independence becomes a condition for ending the Russo-Turkish War.
- 1884 – Pope Leo XIII publishes the encyclical Humanum genus.
- 1898 – U.S. President William McKinley signed a joint resolution to Congress for declaration of War against Spain, beginning the Spanish–American War.[5]
- 1902 – Pierre and Marie Curie refine radium chloride.
- 1908 – Opening day of competition in the New South Wales Rugby League.
- 1912 – Opening day for baseball‘s Tiger Stadium in Detroit, and Fenway Park in Boston.
- 1914 – Nineteen men, women, and children die in the Ludlow Massacre during a Colorado coal-miners’ strike.[6]
- 1916 – The Chicago Cubs play their first game at Weeghman Park (currently Wrigley Field), defeating the Cincinnati Reds 7–6 in 11 innings.
- 1918 – Manfred von Richthofen, a.k.a. The Red Baron, shoots down his 79th and 80th victims, his final victories before his death the following day.
- 1922 – The Soviet government creates South Ossetian Autonomous Oblast within Georgian SSR.
- 1945 – World War II: U.S. troops capture Leipzig, Germany, only to later cede the city to the Soviet Union.
- 1945 – World War II: Führerbunker: On his 56th birthday Adolf Hitler makes his last trip to the surface to award Iron Crosses to boy soldiers of the Hitler Youth.
- 1945 – Twenty Jewish children used in medical experiments at Neuengamme are killed in the basement of the Bullenhuser Damm school.
- 1946 – The League of Nations officially dissolves, giving most of its power to the United Nations.
- 1961 – Cold War: Failure of the Bay of Pigs Invasion of US-backed Cuban exiles against Cuba.
- 1968 – English politician Enoch Powell makes his controversial “Rivers of Blood” speech.
- 1972 – Apollo program: Apollo 16 lunar module, commanded by John Young and piloted by Charles Duke, lands on the moon.
- 1998 – Air France Flight 422 crashes after taking off from El Dorado International Airport in Bogotá, Colombia, killing all 53 people on board.[7]
- 1999 – Columbine High School massacre: Eric Harris and Dylan Klebold killed 13 people and injured 24 others before committing suicide at Columbine High School in Columbine, Colorado.
- 2007 – Johnson Space Center shooting: William Phillips with a handgun barricades himself in NASA‘s Johnson Space Center in Houston, Texas before killing a male hostage and himself.
- 2008 – Danica Patrick wins the Indy Japan 300 becoming the first female driver in history to win an Indy car race.
- 2010 – The Deepwater Horizon drilling rig explodes in the Gulf of Mexico, killing eleven workers and beginning an oil spill that would last six months.
- 2012 – One hundred twenty-seven people are killed when a plane crashes in a residential area near the Benazir Bhutto International Airport near Islamabad, Pakistan.
- 2013 – A 6.6-magnitude earthquake strikes Lushan County, Ya’an, in China’s Sichuan province, killing more than 150 people and injuring thousands.
- 2015 – Ten people are killed in a bomb attack on a convoy carrying food supplies to a United Nations compound in Garowe in the Somali region of Puntland.
-Source: wikipedia