April 23 is the 113th day of the year in the Gregorian Calendar (114th in leap years). There are 252 days remaining.

  1. 215 BC - A temple is built on the Capitoline Hill dedicated to Venus Erycina to commemorate the Roman defeat at Lake Trasimene.
  2. 1014 - Battle of Clontarf: Brian Boru defeats Viking invaders, but is killed in battle.
  3. 1343 - St. George's Night Uprising
  4. 1348 - The founding of the Order of the Garter by King Edward III of England is announced on St George's Day.
  5. 1521 - Battle of Villalar: King Charles I of Spain defeats the Comuneros.
  6. 1533 - The Church of England annuls the marriage between Catherine of Aragon and Henry VIII of England.
  7. 1597 - Shakespeare's The Merry Wives of Windsor is first performed, with Queen Elizabeth I of England in attendance.
  8. 1660 - Treaty of Oliwa is established between Sweden and Poland.
  9. 1661 - King Charles II of England, Scotland and Ireland is crowned in Westminster Abbey.
  10. 1827 - William Rowan Hamilton presents his Theory of systems of rays.
  11. 1867 - William Lincoln patents the zoetrope, a machine which shows animated pictures by mounting a strip of drawings in a wheel.
  12. 1920 - The national council in Turkey denounces the government of Sultan Mehmed VI and announces a temporary constitution.
  13. 1923 - Inauguration ceremonies take place of Gdynia as a temporary military port and fishers' shelter.
  14. 1932 - The 153-year old De Adriaan Windmill in Haarlem, the Netherlands burns down.
  15. 1935 - Polish Constitution of 1935 is adopted.
  16. 1940 - Rhythm Night Club fire at a dance hall in Natchez, Mississippi kills 198 people.
  17. 1941 - World War II: Greek government and King George II evacuate Athens before the attacking Wehrmacht.
  18. 1942 - World War II: Baedeker Blitz – German bombers hit Exeter, Bath and York in retaliation for the British raid on Lübeck.
  19. 1948 - 1948 Arab-Israeli War: Haifa, the major port of Israel, is captured from Palestinian forces.
  20. 1961 - Algiers putsch by French generals.
  21. 1961 - Judy Garland performs at Carnegie Hall.
  22. 1967 - A group of young radicals are expelled from the Nicaraguan Socialist Party (PSN). This group goes on to found the Socialist Workers Party (POS).
  23. 1968 - The United Kingdom produces its first decimalised coins, a 5p and a 10p coin.
  24. 1968 - Vietnam War: Student protesters at Columbia University in New York City take over administration buildings and shut down the university. see main article Columbia University protests of 1968
  25. 1974 - A Pan American World Airways Boeing 707 crashes in Bali, Indonesia, killing 107.
  26. 1979 - Fighting in London between the Anti-Nazi League and the Metropolitan Police's Special Patrol Group results in the death of protestor Blair Peach.
  27. 1987 - 28 construction workers died when the L'Ambiance Plaza collapses while under construction in Bridgeport, Connecticut.
  28. 1990 - Namibia becomes the 160th member of the United Nations and the 50th member of the Commonwealth of Nations.
  29. 1993 - Eritreans vote overwhelmingly for independence from Ethiopia in a United Nations-monitored referendum.
  30. 1994 - Physicists discover the top quark subatomic particle.
  31. 1997 - Omaria massacre in Algeria; 42 villagers killed.
  32. 2003 - Beijing closes all schools for two weeks due to the SARS virus.