August 1st: 30 BCE – Octavian (later known as Augustus) enters Alexandria, Egypt, bringing it under the control of the Roman Republic.

August 2nd: 1990 CE – Iraq invaded Kuwait on this day. 

August 3rd: 1527 CE – First known letter sent from North America by John Rut while at St. John’s, Newfoundland.

August 4th: 1181 CE – Supernova SN 1181 in the constellation Cassiopeia observed by Chinese and Japanese astronomers, lasting until August 6.

August 5th: 882 CE – King Louis III of France died.

August 6th: 1600 CE – Henry IV of France invades Savoy after negotiations break down over Saluzzo, controlled by Savoy since 1588.

August 7th: 322 BCE – Battle of Crannon between Athens and Macedon following the death of Alexander the Great.

August 8th: 1303 CE- Crete earthquake strikes with estimated magnitude of 8, triggering a major tsunami with major damage including ships swept 2 miles inland in Egypt.

August 9th: 1173 CE – Construction of the Tower of Pisa begins, and it takes two centuries to complete.

August 10th: 1628 CE – Swedish warship Vasa sinks in Stockholm, killing 30.

August 11th: 1885 CE – $100,000 raised in the US for a pedestal for the Statue of Liberty.

August 12th: 1492 CE – Christopher Columbus arrived in the Canary Islands on his first voyage to the New World.

August 13th: 1642 CE – Dutch astronomer Christiaan Huygens discovers Mars’ southern polar cap.

August 14th: 1585 CE – Queen Elizabeth I of England refuses sovereignty of Netherlands.

August 15th: 1548 CE – Mary Queen of Scotland arrives in France, age 6.

August 16th: 1691 CE – Yorktown, Virginia founded.

August 17th: 1563 CE – King Charles IX of France was declared an adult at age 13.

August 18th: 1201 CE – The city of Riga was founded.

August 19th: 43 BCE – Octavian, later known as Augustus, compels the Roman Senate to elect him Consul.

August 20th: 2 B.C. Venus and Jupiter in conjunction – possible astrological explanation for Star of Bethlehem.

August 21st: 1772 CE – King Gustav III of Sweden completes a coup d’etat by adopting a new Constitution and installing himself as an enlightened despot, ending 50 years of parliamentary rule.

August 22nd: 1642 CE – English Civil War begins between Royalists and Parliament.

August 23rd: 79 CE – Mount Vesuvius begins stirring, on feast day of Vulcan, Roman god of fire goes on to destroy Pompeii on [approximate date] 

August 24th: 79 CE – Believed until 2018 to be the date of the massive eruption of Mt. Vesuvius which buried the cities of Pompeii, Herculaneum, Oplontis, and Stabiae, killing untold thousands. Latest evidence suggests the eruption occurred after the 17th of October.

August 25th: 1609 CE – Galileo demonstrates his first telescope to Venetian lawmakers.

August 26th: 1682 CE – English astronomer Edmond Halley first observes the comet named after him.

August 27th: 1789 CE – French National Assembly issues the “Declaration of Rights of Man and Citizen”.

August 28th: 1963 CE – Martin Luther King Jr. delivers his “I have a dream” speech.

August 29th: 2005 CE – Hurricane Katrina makes 2nd and 3rd landfall as a category 3 hurricane.

August 30th: 1862 CE – Second Battle of Bull Run in Manassas, Virginia, ends with a Confederate victory over Union forces.

August 31st: 1945 CE – The Liberal Party of Australia was founded by Robert Menzies.

Cites:

http://www.onthisday.com

https://www.usatoday.com/videos/news/nation/2022/08/21/today-history-august-21st/7859970001/