919 – The nobles of Franconia and Saxony elect Henry the Fowler at the Imperial Diet in Fritzlar as king of the East Frankish Kingdom.
1218 – The Fifth Crusade leaves Acre for Egypt.
1276 – Magnus Ladulås is crowned King of Sweden in Uppsala Cathedral.
1487 – The ten-year-old Lambert Simnel is crowned in Christ Church Cathedral, Dublin, Ireland, with the name of Edward VI in a bid to threaten King Henry VII's reign.
1595 – Nomenclator of Leiden University Library appears, the first printed catalog of an institutional library.
1607 – 100 English settlers disembark in Jamestown, the first English colony in America.
1621 – The Protestant Union is formally dissolved.
1626 – Peter Minuit buys Manhattan.
1667 – The French Royal Army crosses the border into the Spanish Netherlands, starting the War of Devolution opposing France to the Spanish Empire and the Triple Alliance.
1689 – The English Parliament passes the Act of Toleration protecting Protestants; Roman Catholics are excluded.
1738 – John Wesley is converted, essentially launching the Methodist movement; the day is celebrated annually by Methodists as Aldersgate Day and a church service is generally held on the preceding Sunday.
1798 – The Irish Rebellion of 1798 led by the United Irishmen against British rule begins.
1813 – South American independence leader Simón Bolívar enters Mérida, leading the invasion of Venezuela, and is proclaimed El Libertador ("The Liberator").
1822 – Battle of Pichincha: Antonio José de Sucre secures the independence of the Presidency of Quito.
1830 – "Mary Had a Little Lamb" by Sarah Josepha Hale is published.
1832 – The First Kingdom of Greece is declared in the London Conference.
1844 – Samuel Morse sends the message "What hath God wrought" (a biblical quotation, Numbers 23:23) from the Old Supreme Court Chamber in the United States Capitol to his assistant, Alfred Vail, in Baltimore, Maryland, to inaugurate the first telegraph line.
1856 – John Brown and his men kill five slavery supporters at Pottawatomie Creek, Kansas.
1861 – American Civil War: Union troops occupy Alexandria, Virginia.
1883 – The Brooklyn Bridge in New York City is opened to traffic after 14 years of construction.
1895 – Henry Irving becomes the first person from the theatre to be knighted.
1900 – Second Boer War: The United Kingdom annexes the Orange Free State.
1915 – World War I: Italy declares war on Austria-Hungary, joining the conflict on the side of the Allies.
1921 – The trial of Sacco and Vanzetti opens.
1930 – Amy Johnson lands in Darwin, Northern Territory, becoming the first woman to fly solo from England to Australia (she left on May 5 for the 11,000 mile flight).
1935 – The first night game in Major League Baseball history is played in Cincinnati, Ohio, with the Cincinnati Reds beating the Philadelphia Phillies 2–1 at Crosley Field.
1940 – Igor Sikorsky performs the first successful single-rotor helicopter flight.
1940 – Acting on the orders of Soviet leader Joseph Stalin, NKVD agent Iosif Grigulevich orchestrates an unsuccessful assassination attempt on exiled Russian revolutionary Leon Trotsky in Coyoacán, Mexico.
1941 – World War II: In the Battle of the Atlantic, the German Battleship Bismarck sinks then-pride of the Royal Navy, HMS Hood, killing all but three crewmen.
1948 – Arab–Israeli War: Egypt captures the Israeli kibbutz of Yad Mordechai, but the five-day effort gives Israeli forces time to prepare enough to stop the Egyptian advance a week later.
1950 – United Nations Security Council Resolution 81 is adopted.
1956 – Conclusion of the Sixth Buddhist Council on Vesak Day, marking the 2,500 year anniversary after the Lord Buddha's Parinibbāna.
1956 – The first Eurovision Song Contest is held in Lugano, Switzerland.
1958 – United Press International is formed through a merger of the United Press and the International News Service.
1960 – Following the 1960 Valdivia earthquake, the largest ever recorded earthquake, Cordón Caulle begins to erupt.
1961 – American civil rights movement: Freedom Riders are arrested in Jackson, Mississippi, for "disturbing the peace" after disembarking from their bus.
1961 – Cyprus joins the Council of Europe.
1962 – Project Mercury: American astronaut Scott Carpenter orbits the Earth three times in the Aurora 7 space capsule.
1967 – Egypt imposes a blockade and siege of the Red Sea coast of Israel.
1976 – The Judgment of Paris takes place in France, launching California as a worldwide force in the production of quality wine.
1981 – Ecuadorian president Jaime Roldós Aguilera, his wife, and his presidential committee die in an aircraft accident while travelling from Quito to Zapotillo minutes after the president gave a famous speech regarding the 24 de mayo anniversary of the Battle of Pichincha.
1982 – Liberation of Khorramshahr: Iranians recapture of the port city of Khorramshahr from the Iraqis during the Iran–Iraq War.
1988 – Section 28 of the United Kingdom's Local Government Act 1988, a controversial amendment stating that a local authority cannot intentionally promote homosexuality, is enacted.
1991 – Israel conducts Operation Solomon, evacuating Ethiopian Jews to Israel.
1992 – The last Thai dictator, General Suchinda Kraprayoon, resigns following pro-democracy protests.
1992 – The ethnic cleansing in Kozarac, Bosnia and Herzegovina begins when Serbian militia and police forces enter the town.
1993 – Eritrea gains its independence from Ethiopia.
1994 – Four men convicted of bombing the World Trade Center in New York in 1993 are each sentenced to 240 years in prison.
1999 – The International Criminal Tribunal for the former Yugoslavia in The Hague, Netherlands indicts Slobodan Milošević and four others for war crimes and crimes against humanity committed in Kosovo.
2000 – Israeli troops withdraw from southern Lebanon after 22 years of occupation.
2001 – Mountaineering: Temba Tsheri, a 16-year-old Sherpa, becomes the youngest person to climb to the top of Mount Everest.
2001 – The Versailles wedding hall disaster in Jerusalem kills 23 and injures over 200.
2002 – Russia and the United States sign the Moscow Treaty.
2014 – A 6.4 magnitude earthquake occurs in the Aegean Sea between Greece and Turkey, injuring 324 people.
2014 – At least three people are killed in a shooting at Brussels' Jewish Museum of Belgium.