1. 305 - Diocletian and Maximian retire as Roman emperors.

2. 524 - King Sigismund of Burgundy is executed at Orleans after an eight - year reign and is succeeded by his brother Godomar.

3. 880 - The Nea Ekklesia is inaugurated in Constantinople, setting the model for all later cross - in - square Orthodox churches.

4. 1328 - The Scottish Wars of Independence end: The Treaty of Edinburgh - Northampton leads the Kingdom of England to agree to recognize the Kingdom of Scotland as an independent state.

5. 1351 - Zurich becomes part of Switzerland.

6. 1460 - Italian seafarer Antonio de Noli, sailing for Portugal, discovers the Cape Verde island of Maio, which he names after the date of his discovery.

7. 1464 - Edward IV of England marries Elizabeth Woodville.

8. 1707 - The Act of Union joins Scotland and England.

9. 1759 - Josiah Wedgwood founds the Wedgwood pottery company.

10. 1776 - The Illuminati are founded in Ingolstadt, Bavaria, by Adam Weishaupt.

11. 1778 - American Revolution: The Battle of Crooked Billet begins in Hatboro, Pennsylvania.

12. 1785 - Kamehameha I, King of Hawaii, defeats Kalani Kupule, creating the Kingdom of Hawaii.

13. 1786 - The opera, The Marriage of Figaro by Wolfgang Amadeus Mozart, is performed for the first time in Vienna, Austria.

14. 1794 - War of the Pyrenees: The Battle of Boulou ends, in which French forces defeat the Spanish and regain almost the land they had lost to Spain in 1793.

15. 1834 - British colonies abolish slavery.

16. 1840 - The Penny Black postage stamp is introduced in the UK.

17. 1844 - The Hong Kong police force is founded.

18. 1851 - Queen Victoria announces the beginning of the Great Exhibition in London.

19. 1852 - The Philippine peso is introduced into circulation.

20. 1856 - The province of Isabela is created in the Philippines.

21. 1863 - The stainless banner is adopted as the flag of the Confederate States of America.

22. 1863 - American Civil War: The Battle of Chancellorsville begins.

23. 1865 - Brazil, Argentina, and Uruguay sign the Treaty of the Triple Alliance.

24. 1875 - Alexandra Palace in London re - opens after being burned down in a fire in 1873.

25. 1884 - Moses Fleetwood Walker becomes the first African - American to play a professional baseball game in the US.

26. 1886 - In Chicago, USA, over 200,000 workers go on a general strike, demanding the implementation of an eight - hour workday.

27. 1893 - The World's Columbian Exposition opens in Chicago.

28. 1898 - Spanish - American War: Battle of Manila Bay - The United States Navy destroys the Spanish Pacific fleet in the first battle of the war.

29. 1900 - The Scofield mine disaster in Utah kills 200 men.

30. 1914 - Yuan Shikai promulgates the "Constitution of the Republic of China".

31. 1920 - China commemorates "May 1" International Labor Day for the first time.

32. 1923 - Joseph Heller, an acclaimed American author, is born.

33. 1931 - The Empire State Building is officially opened by President Herbert Hoover.

34. 1945 - World War II: Nazi Germany surrenders unconditionally.

35. 1950 - The entire territory of Hainan Island is liberated.

36. 1961 - The first group of Freedom Riders embarks on a bus journey through the American South to challenge racial segregation.

37. 1970 - The Beatles release their final studio album, "Let It Be".

38. 1984 - The Los Angeles Olympics open.

39. 1991 - The Warsaw Pact is officially dissolved.

40. 2001 - The euro is introduced as legal tender in 12 European Union countries.

41. 2004 - Ten new countries join the European Union, bringing the total number of member states to 25.

42. 2005 - North Korea fires a missile.

43. 2010 - The Shanghai World Expo opens.

44. 2015 - The Milan World Expo opens near Milan, Italy.

45. 2017 - JR East's luxury cruise train, TRAIN SUITE Shiki - shima, begins operation.

46. 2018 - American musical instrument maker Gibson applies for Chapter 11 bankruptcy protection.

47. 2019 - Emperor Akihito abdicates on April 30, and Crown Prince Naruhito ascends the throne at 00:00 on May 1.

48. 2020 - The World Health Organization declares that the COVID - 19 pandemic is a public health emergency of international concern.

49. 2021 - The European Union begins to vaccinate its citizens against COVID - 19.

50. 2024 - Scientists announce a major breakthrough in the development of a new energy - saving material.