• 1176 - The Battle of Myriokephalon is fought.
• 1462 - The Battle of Świecino (or Battle of Żarnowiec) is fought during Thirteen Years' War.
• 1577 - Peace of Bergerac signed between Henry III of France and the Huguenots.
• 1630 - The city of Boston, Massachusetts, is founded.
• 1631 - Sweden wins a major victory at the Battle of Breitenfeld against the Holy Roman Empire during the Thirty Years War.
• 1776 - The Presidio of San Francisco is founded in New Spain.
• 1778 - Treaty of Fort Pitt signed, the first formal treaty between the United States and a Native American tribe (the Lenape or Delaware).
• 1787 - The United States Constitution is signed in Philadelphia, Pennsylvania.
• 1809 - Peace between Sweden and Russia in the Finnish War. The territory to become Finland is ceded to Russia by the Treaty of Fredrikshamn.
• 1814 - Francis Scott Key finishes his The Star-Spangled Banner poem.
• 1859 - Joshua A. Norton declares himself Emperor Norton I of the United States.
• 1862 - American Civil War: George B. McClellan halts the northward drive of Robert E. Lee's Confederate army in the single-day Battle of Antietam, the bloodiest day in American history.
• 1862 - American Civil War: The Allegheny Arsenal explosion resulted in the single largest civilian disaster during the war
• 1894 - Battle of Yalu River, the largest naval engagement of the First Sino-Japanese War.
• 1900 - Philippine-American War: Filipinos under Juan Cailles defeat Americans under Colonel Benjamin F. Cheatham at Mabitac.
• 1908 - The Wright Flyer flown by Orville Wright, with Lieutenant Thomas Selfridge as passenger, crashes; killing Selfridge. He becomes the first airplane fatality.
• 1914 - Andrew Fisher becomes Prime Minister of Australia for the third time.
• 1916 - World War I: Manfred von Richthofen ("The Red Baron"), a flying ace of the German Luftstreitkräfte, won his first aerial combat near Cambrai, France.
• 1920 - National Football League is organized in Canton, Ohio, United States.
• 1924 - The Border Defence Corps was established in the Second Polish Republic for the defence of the eastern border against armed Soviet raids and local bandits.
• 1928 - The Okeechobee Hurricane strikes southeastern Florida, killing upwards of 2,500 people. It is the third deadliest natural disaster in US history, behind the Galveston Hurricane of 1900 and the 1906 San Francisco earthquake.
• 1939 - The Soviet Union joined Nazi Germany's invasion of Poland during the Polish Defensive War of 1939.
• 1939 - World War II: A German U-boat U 29 sinks the British aircraft carrier HMS Courageous.
• 1941 - A decree of the Soviet State Committee of Defense, restoring Vsevobuch in the face of the Great Patriotic War, was issued
• 1943 - Russian city of Bryansk liberated from Nazis.
• 1944 - Allied Airborne troops parachute into the Netherlands as the "Market" half of Operation Market Garden.
• 1947 - James V. Forrestal was sworn in as the first Secretary of Defense of United States.
• 1948 - Lehi (also known as the Stern gang) assassinates Count Folke Bernadotte, who was appointed by the UN to mediate between the Arabs and Jews.
• 1949 - The Canadian steamship SS Noronic burns in Toronto Harbor with the loss of over 118 lives.
• 1956 - Television was first broadcast in Australia.
• 1957 - The North East Humanists group was founded in Newcastle upon Tyne.
• 1967 - Jim Morrison and The Doors defy CBS censors on The Ed Sullivan Show.
• 1970 - Fighting breaks out along the Syria-Jordanian border between Jordanian troops and the fedayeen.
• 1976 - The first Space Shuttle, Enterprise, was unveiled by NASA.
• 1978 - The Camp David Accords were signed by Israel and Egypt.
• 1983 - Vanessa Williams becomes the first black Miss America.
• 1991 - North Korea, South Korea, Estonia, Latvia, Lithuania, the Marshall Islands and Micronesia join the United Nations.
• 1991 - The first version of the Linux kernel (0.01) is released to the Internet.
• 1991 - Guns N' Roses' much-anticipated albums Use Your Illusion I and II were finally released.
• 1993 - Last Russian troops leave Poland.
• 2001 - The New York Stock Exchange opened for the first time since the September 11 attacks; the Dow Jones Industrial Average posted its biggest point drop in its history, closing down 684.81 points to 8920.70.
• 2004 - Tamil is declared the first classical language in India.
• 2007 - AOL, once the largest ISP in the U.S., officially announces plans to refocus the company as an advertising business and to relocate its corporate headquarters from Dulles, Virginia to New York, New York.

Births