1. 238 - Year of the Six Emperors: The Roman Senate outlaws Emperor Maximus Thrax for his bloodthirsty proscriptions in Rome and nominates two of its members, Pupienus and Balbinus, to the throne.

2. 296 - St. Gaius ends his reign as Catholic pope.

3. 536 - St. Agapetus I ends his reign as Catholic pope.

4. 1056 - Supernova crab nebula last seen by the naked eye.

5. 1073 - Pope Alexander II is buried and Ildebrando is chosen as Pope Gregory VII.

6. 1145 - 19th recorded perihelion passage of Halley's comet.

7. 1164 - Raynald of Dassel names Guido di Crema as anti - Pope Paschalis III.

8. 1370 - Building begins on the Bastille fortress in Paris.

9. 1500 - Pedro Álvares Cabral is the first European to discover Brazil, landing near Monte Pascoal, claims it for Portugal.

10. 1509 - Henry VIII, 2nd Tudor king of England, ascends to the throne at age 17, after the death of his father, Henry VII.

11. 1519 - Hernán Cortés establishes a settlement in Veracruz, Mexico.

12. 1521 - French King Francis I declares war on Spain.

13. 1526 - 1st slave revolt in North America at San Miguel de Gualdape, a Spanish settlement (now part of South Carolina).

14. 1529 - Treaty of Saragosa: Spain and Portugal divide the eastern hemisphere.

15. 1659 - Lord Protector Richard Cromwell disbands the English parliament.

16. 1674 - The Netherlands and Munster sign a peace treaty.

17. 1676 - Battle of Etna - The Netherlands and Spain vs France, M de Ruyter fatally wounded.

18. 1677 - Battle at Catania: between the French and Dutch fleets.

19. 1692 - Edward Bishop is jailed for proposing flogging as a cure for witchcraft in Salem, Massachusetts.

20. 1722 - 19 VOC "Komp Lotteurs" in Batavia are executed.

21. 1728 - Pierre de Marivaux's "Le Triomphe de Plutus" premieres in Paris.

22. 1745 - Austria and Bavaria sign the peace treaty of Füssen, ending Bavaria's participation (on the French side) in the War of the Austrian Succession.

23. 1769 - Madame du Barry becomes French King Louis XV's "official" mistress.

24. 1792 - US President George Washington proclaims American neutrality in the war in Europe.

25. 1793 - President Washington attends the opening of Rickett's, the 1st circus in the US.

26. 1804 - Gioachino Rossini performs as a singer in Imola, Italy, aged only 12 years old.

27. 1809 - Battle of Eckmühl: Napoleon's French and Bavarian forces defeat the Austrians under Archduke Charles at Eggmühl, Bavaria, giving Napoleon the strategic initiative for the rest of the War of the Fifth Coalition.

28. 1817 - Curaçao prohibits the use of white paint due to fierce sunlight.

29. 1823 - The Baltic Club (exchange) forms in London.

30. 1823 - British inventor Robert John Tyers patents an in - line roller skate he calls the "Voli to", with a single row of 5 wooden wheels, a wooden sole, and a curved iron bar at the front as a rudimentary brake.

31. 1836 - Texas Revolution: A day after the Battle of San Jacinto, forces under Texas General Sam Houston capture Mexican General Antonio López de Santa Anna.

32. 1838 - The English steamship "Sirius" docks in NYC after crossing the Atlantic, the first transatlantic steam passenger service.

33. 1861 - Robert E. Lee is named commander of Virginia forces.

34. 1863 - American Civil War: Grierson's Raid begins – troops under Union Colonel Benjamin Grierson attack central Mississippi.

35. 1864 - The United States Congress passes the Coinage Act which mandates that the inscription "In God We Trust" be placed on all coins minted as United States currency.

36. 1864 - The US mints a 2 - cent coin (the 1st appearance of "In God We Trust").

37. 1876 - The first - ever National League baseball game is played.

38. 1889 - The Oklahoma Land Rush begins at noon, as thousands of homesteaders rush to claim land in what is now the state of Oklahoma.

39. 1898 - Spanish - American War: The United States Navy begins a blockade of Cuban ports and the USS Nashville captures a Spanish merchant ship.

40. 1906 - The start of the 1906 summer Olympics in Athens. They are not officially counted as part of the modern Olympic games.

41. 1906 - The end of the Mount Vesuvius eruption that started on April 4. In total, 1,000 people are estimated to have died as a result of the effects from the eruption.

42. 1911 - Tsinghua University, one of China's top universities, is founded.

43. 1912 - Pravda begins publication in Saint Petersburg, known as the "voice" of the Communist Party of the Soviet Union.

44. 1914 - Babe Ruth, age 19, pitches his first professional game for the minor - league Baltimore Orioles.

45. 1915 - The use of poison gas in World War I escalates when chlorine gas is released as a chemical weapon in the Second Battle of Ypres.

46. 1930 - The United Kingdom, Japan, and the United States sign the London Naval Treaty regulating submarine warfare and limiting shipbuilding.

47. 1931 - Egypt signs the Treaty of Friendship with Iraq.

48. 1943 - Albert Hofmann writes his first report about the hallucinogenic properties of LSD.

49. 1944 - World War II: Operation Persecution is initiated – Allied forces land in the Hollandia area of New Guinea.

50. 1952 - An atomic test conducted in Nevada is the first nuclear explosion shown on live network television.