1122 - Concordat of Worms.
1459 - Battle of Blore Heath, the first major battle of the English Wars of the Roses, is fought at Blore Heath in Staffordshire.
1529 - The Siege of Vienna begins as Suleiman I begins his attack on the city.
1641 - The Merchant Royal, carrying a treasure worth over a billion USD, is lost at sea off Land's End.
1642 - First commencement exercises occur at Harvard College.
1779 - American Revolution: a squadron commanded by John Paul Jones on board the USS Bonhomme Richard wins the Battle of Flamborough Head, off the coast of England, against two British warships.
1780 - American Revolution: British Major John André is arrested as a spy by American soldiers exposing Benedict Arnold's treason.
1803 - Second Anglo-Maratha War: Battle of Assaye.
1806 - Lewis and Clark return to St. Louis, after exploring the Pacific Northwest of the United States.
1818 - Border demarcation markers for Neutral Moresnet are formally installed.
1821 - Tripolitsa, Greece, falls and 30,000 Turks are massacred.
1845 - The Knickerbockers Baseball Club, the first baseball team to play under the modern rules, is founded in New York.
1846 - Neptune is discovered by French astronomer Urbain Jean Joseph Le Verrier and British astronomer John Couch Adams; the discovery is verified by German astronomer Johann Gottfried Galle.
1868 - Grito de Lares (Lares Revolt) occurs in Puerto Rico against Spanish rule.
1889 - Nintendo Koppai (Later Nintendo Company, Limited) is founded by Fusajiro Yamauchi to produce and market the playing card game Hanafuda.
1905 - Norway and Sweden sign the "Karlstad treaty", peacefully dissolving the Union between the two countries.
1908 - University of Alberta in Alberta, Canada, is founded.
1922 - Gdynia Seaport Construction Act is passed by the Polish parliament.
1932 - The Kingdom of Hejaz and Nejd is renamed the Kingdom of Saudi Arabia.
1938 - Mobilization of the Czechoslovak army in response to the Munich Crisis.
1941 - World War II: The first gas murder experiments are conducted at Auschwitz.
1942 - World War II: First day of the September Matanikau action on Guadalcanal as United States Marine Corps forces attack Imperial Japanese Army units along the Matanikau River.
1952 - Richard Nixon makes his "Checkers speech".
1959 - The M/S Princess of Tasmania Australia’s first passenger RO/RO diesel ferry makes her maiden voyage across Bass Strait.
1962 - The Lincoln Center for the Performing Arts in New York City opens with the completion of the first building, the Philharmonic Hall (now Avery Fisher Hall) home of the New York Philharmonic.
1969 - The Chicago Eight trial opens in Chicago.
1972 - Philippine President Ferdinand Marcos announces over television and radio the implementation of martial law and signs General Order No. 1 ordering the arrest of opposition leaders, media censorship, banning travel to other countries except for diplomatic missions, abolishing the Philippine Congress, establishing dictatorial government, take-over or sequestering of public and private corporations and suspension of classes for one week.
1973 - Juan Perón returns to power in Argentina.
1983 - Saint Kitts and Nevis joins the United Nations.
1983 - Gerrie Coetzee of South Africa becomes the first African boxing world heavyweight champion.
1988 - José Canseco of the Oakland Athletics becomes the first member of the 40-40 club.
1992 - A large Provisional Irish Republican Army bomb destroys the forensic laboratories in Belfast.
1999 - NASA announces that it has lost contact with the Mars Climate Orbiter.
1999 - Qantas Flight 1 overruns the runway in Bangkok during a storm. While some passengers only receive minor injuries, it is still the worst crash in Qantas's history since 1960.
2002 - The first public version of the web browser Mozilla Firefox ("Phoenix 0.1") is released.
2004 - At least 1,070 in Haiti are reported killed by floods due to Hurricane Jeanne
2005 - FBI killing of Filiberto Ojeda on Plan Bonito Hormigueros, Puerto Rico.