May 21

• May 21, 987
  French King Louis V dies from a fall while hunting, terminating the Carolingian period of Frankish rule
• May 21, 996
  Otto III is crowned the Roman Emperor by his cousin Pope Gregory V
• May 21, 1420
  King Charles VI of France signs the Treaty of Troyes that recognizes all the territorial gains of King Henry V of England, gives Henry the daughter of Charles in marriage, and acknowledges Henry as the legitimate heir to the French throne
• May 21, 1471
  Henry VI, king of England and France, is killed in the tower of London and Edward IV takes the throne
• May 21, 1535
  Imperial authorities in Antwerp capture and imprison William Tyndale for heresy over his translation of the Bible into English
• May 21, 1542
  Spanish explorer Hernando De Soto dies while searching for gold along the Mississippi River and is buried by his men in the Mississippi River in what is now Louisiana in order that Indians would not learn of his death, and thus disprove de Soto's claims of divinity
• May 21, 1674
  General John Sobieski is chosen King of Poland
• May 21, 1683
  The Society of Suriname, a Dutch private company, is founded by the city of Amsterdam, the Van Aerssen van Sommelsdijck family, and the Dutch West India Company
• May 21, 1809
  Austrian archduke Charles beats Napoleon at Battle of Aspern-Essling when he was crossing the Danube near Vienna, which becomes the first personally defeat of Napoleon over a decade
• May 21, 1840
  New Zealand is founded as a British colony since the Treaty of Waitangi is signed by Māori chiefs of New Zealand and representatives of Queen Victoria
• May 21, 1871
  French government troops enter in Paris and attack the Commune of Paris
• May 21, 1881
  Clara Barton, a hospital nurse, founds American Red Cross
• May 21, 1881
  Standard Oil, an American oil producing founded by John D. Rockefeller, becomes the world's first trust, after thirty-seven stockholders convey their shares
• May 21, 1916
  Britain begins "Summer Time", which becomes the implementation of daylight saving time
• May 21, 1927
  Charles Lindbergh, an American aviator, becomes the first person who makes solo non-stop transatlantic flight, from New York's Long Island to Le Bourget Field in Paris
• May 21, 1945
  German war criminal Heinrich Himmler is captured
• May 21, 1998
  Suharto forced to resign as president of Indonesia after 31-year reign