October 6
- 105 BC – Battle of Arausio: The Cimbri inflict the heaviest defeat on the Roman army of Gnaeus Mallius Maximus.
- 69 BC – Battle of Tigranocerta: Forces of the Roman Republic defeat the army of the Kingdom of Armenia led by King Tigranes the Great.
- 68 BC – Battle of Artaxata: Lucullus averts the bad omen of this day by defeating Tigranes the Great of Armenia.
- 404 – Empress Eudoxia has her seventh and last pregnancy who ends in a miscarriage. She is left bleeding and dies of an infection short after.
- 1582 – Because of the implementation of the Gregorian calendar, this day is skipped in Italy, Poland, Portugal and Spain.
- 1600 – Jacopo Peri's Euridice, the earliest surviving opera, receives its première performance in Florence, signifying the beginning of the Baroque Period
- 1683 – German immigrant families found Germantown in the colony of Pennsylvania, marking the first major immigration of German people to America.
- 1762 – Seven Years' War: conclusion of the Battle of Manila between Britain and Spain, which resulted in the British occupation of Manila for the rest of the war.
- 1777 – American Revolutionary War: General Sir Henry Clinton leads British forces in the capture of Continental Army Hudson River defenses in the Battle of Forts Clinton and Montgomery.
- 1789 – French Revolution: Louis XVI returns to Paris from Versailles after being confronted by the Parisian women on 5 October
- 1849 – The execution of the 13 Martyrs of Arad after the Hungarian war of independence.
- 1854 – The Great fire of Newcastle and Gateshead starts shortly after midnight, leading to 53 deaths and hundreds injured.
- 1876 – The American Library Association was founded.
- 1884 – The Naval War College of the United States Navy is founded in Newport, Rhode Island.
- 1889 – Thomas Edison shows his first motion picture.
- 1898 – Ossian Everett Mills founds Phi Mu Alpha Sinfonia in Boston, Massachusetts.
- 1903 – The High Court of Australia sat for the first time.
- 1908 – Austria annexes Bosnia and Herzegovina.
- 1910 – Eleftherios Venizelos is elected Prime Minister of Greece for the first time (7 times in total).
- 1923 – The great powers of World War I withdraw from Istanbul
- 1927 – Opening of The Jazz Singer, the first prominent talking movie.
- 1939 – World War II: The last Polish army is defeated.
- 1945 – Baseball: Billy Sianis and his pet billy goat are ejected from Wrigley Field during Game 4 of the 1945 World Series (see Curse of the Billy Goat).
- 1973 – Egypt launches a coordinated attack with Syria against Israel leading to the Yom Kippur War.
- 1976 – Cubana Flight 455 crashes into the Atlantic Ocean shortly after taking off from Bridgetown, Barbados after two bombs, placed on board by terrorists with connections to the CIA, exploded. All 73 people on board are killed.
- 1976 – New Premier Hua Guofeng orders the arrest of the Gang of Four and associates and ends the Cultural Revolution in the People's Republic of China.
- 1976 – Massacre of students gathering at Thammasat University in Bangkok, Thailand to protest the return of ex-dictator Thanom, by a coalition of right-wing paramilitary and government forces, triggering the return of the military to government.
- 1977 – In Alicante, Spain, fascists attack a group of MCPV militants and sympathizers, and one MCPV sympathizer is killed.
- 1977 – The first prototype of the MiG-29, designated 9-01, makes its maiden flight.
- 1979 – Pope John Paul II becomes the first pontiff to visit the White House.
- 1981 – Egyptian President Anwar al-Sadat is assassinated.
- 1985 – PC Keith Blakelock is murdered as riots erupt in the Broadwater Farm suburb of London.
- 1987 – Fiji becomes a republic.
- 1995 – 51 Pegasi is discovered to be the first major star apart from the Sun to have a planet (and extrasolar planet) orbiting around it.
- 2000 – Yugoslav president Slobodan Milošević resigns.
- 2000 – Argentine vice president Carlos Álvarez resigns.
- 2002 – The French oil tanker Limburg is bombed off Yemen.
- 2007 – Jason Lewis completes the first human-powered circumnavigation of the globe.
October 5
- 610 – Coronation of Byzantine Emperor Heraclius
- 869 – The Fourth Council of Constantinople is convened to decide about what to do about Patriarch Photius of Constantinople.
- 1143 – King Alfonso VII of León recognises Portugal as a Kingdom.
- 1450 – Jews are expelled from Lower Bavaria by order of Louis IX, Duke of Bavaria.
- 1550 – Foundation of Concepción, city in Chile.
- 1582 – Because of the implementation of the Gregorian calendar this day does not exist in this year in Italy, Poland, Portugal and Spain.
- 1665 – The University of Kiel is founded.
- 1789 – French Revolution: Women of Paris march to Versailles in the March on Versailles to confront Louis XVI about his refusal to promulgate the decrees on the abolition of feudalism, demand bread, and have the King and his court moved to Paris.
- 1793 – French Revolution: Christianity is disestablished in France.
- 1813 – Battle of Thames in Canada; Americans defeat British.
- 1857 – The City of Anaheim is founded.
- 1864 – The Indian city of Calcutta is almost totally destroyed by a cyclone; 60,000 die.
- 1869 – The Saxby Gale devastates the Bay of Fundy region of Maritime Canada. The storm had been predicted over a year before by a British naval officer.
- 1877 – Chief Joseph surrenders his Nez Perce band to General Nelson A. Miles.
- 1895 – The first individual time trial for racing cyclists is held on a 50-mile course north of London.
- 1903 – Sir Samuel Griffith is appointed the first Chief Justice of Australia and Sir Edmund Barton and Richard O'Connor are appointed as foundation justices.
- 1905 – Wilbur Wright pilots Wright Flyer III in a flight of 24 miles in 39 minutes, a world record that stood until 1908.
- 1910 – In a revolution in Portugal the monarchy is overthrown and a republic is declared .
- 1914 – World War I: first aerial combat resulting in a kill.
- 1915 – Bulgaria enters World War I as one of the Central Powers.
- 1921 – Baseball: The World Series is broadcast on the radio for the first time.
- 1930 – British Airship R101 crashes in France en-route to India on its maiden voyage.
- 1936 – The Jarrow March sets off for London.
- 1944 – Royal Canadian Air Force pilots shoot down the first German jet fighter over France.
- 1944 – Suffrage is extended to women in France.
- 1945 – Hollywood Black Friday: A six-month strike by Hollywood set decorators turns into a bloody riot at the gates of Warner Brothers' studios.
- 1947 – The first televised White House address is given by U.S. President Harry S. Truman.
- 1948 – The 1948 Ashgabat earthquake kills 110,000.
- 1953 – The first documented recovery meeting of Narcotics Anonymous is held.
- 1962 – Dr. No, the first in the James Bond film series, is released.
- 1966 – Near Detroit, Michigan, there is a partial core meltdown at the Enrico Fermi demonstration nuclear breeder reactor.
- 1968 – Police baton civil rights demonstrators in Derry, Northern Ireland – considered to mark the beginning of The Troubles.
- 1969 – The first episode of Monty Python's Flying Circus airs on BBC.
- 1970 – The Public Broadcasting Service (PBS) is founded.
- 1970 – Montreal, Quebec: British Trade Commissioner James Cross is kidnapped by members of the FLQ terrorist group, triggering the October Crisis.
- 1973 – Signature of the European Patent Convention.
- 1974 – Guildford pub bombings: bombs planted by the Provisional Irish Republican Army (IRA) kill four British soldiers and one civilian.
- 1981 – Raoul Wallenberg becomes an honorary U.S. citizen.
- 1982 – Chicago Tylenol murders: Johnson & Johnson initiates a nationwide product recall in the United States for all products in its Tylenol brand after several bottles in Chicago are found to have been laced with cyanide, resulting in seven deaths.
- 1984 – Marc Garneau becomes the first Canadian in space, aboard the Space Shuttle Challenger.
- 1986 – Israeli secret nuclear weapons are revealed. The British newspaper The Sunday Times runs Mordechai Vanunu's story on its front page under the headline: "Revealed — the secrets of Israel's nuclear arsenal".
- 1988 – The Chilean opposition coalition Concertación (center-left) defeats Augusto Pinochet in his re-election attempt and a general election is called the following year.
- 1990 – After one hundred and fifty years The Herald broadsheet newspaper in Melbourne, Australia, is published for the last time as a separate newspaper.
- 1991 – An Indonesian military transport crashes after takeoff from Jakarta killing 137.
- 1991 – The first official version of the Linux kernel, version 0.02, is released.
- 1999 – The Ladbroke Grove rail crash in west London kills 31 people.
- 2000 – Mass demonstrations in Belgrade lead to resignation of Serbian strongman Slobodan Milošević. These demonstrations are often called the Bulldozer Revolution.
- 2001 – Robert Stevens becomes the first victim in the 2001 anthrax attacks.
October 4
- 610 – Heraclius arrives by ship from Africa at Constantinople, overthrows Byzantine Emperor Phocas and becomes Emperor.
- 1227 – Assassination of Caliph al-Adil.
- 1363 – End of the Battle of Lake Poyang; the Chinese rebel forces of Zhu Yuanzhang defeat that of his rival, Chen Youliang, in one of the largest naval battles in history.
- 1511 – Formation of the Holy League of Ferdinand II of Aragon, the Papal States and the Republic of Venice against France.
- 1535 – The first complete English-language Bible (the Coverdale Bible) is printed, with translations by William Tyndale and Miles Coverdale.
- 1582 – Pope Gregory XIII implements the Gregorian Calendar. In Italy, Poland, Portugal, and Spain, October 4 of this year is followed directly by October 15.
- 1636 – The Swedish Army defeats the armies of Saxony and the Holy Roman Empire at the Battle of Wittstock.
- 1693 – Battle of Marsaglia: Piedmontese troops are defeated by the French.
- 1725 – Foundation of Rosario in Argentina.
- 1777 – Battle of Germantown: Troops under George Washington are repelled by British troops under Sir William Howe.
- 1779 – The Fort Wilson Riot takes place.
- 1795 – Napoleon Bonaparte first rises to national prominence with a "Whiff of Grapeshot", using cannon to suppress armed counter-revolutionary rioters threatening the French Legislature (National Convention).
- 1824 – Mexico adopts a new constitution and becomes a federal republic.
- 1830 – Creation of the state of Belgium after separation from The Netherlands.
- 1853 – Crimean War: The Ottoman Empire declares war on Russia.
- 1876 – Texas A&M University opens as the Agricultural and Mechanical College of Texas, becoming the first public institution of higher education in Texas.
- 1883 – First run of the Orient Express.
- 1883 – First meeting of the Boys' Brigade in Glasgow, Scotland.
- 1895 – The first U.S. Open Men's Golf Championship administered by the United States Golf Association is played at the Newport Country Club in Newport, Rhode Island.
- 1918 – An explosion kills more than 100 and destroys the T.A. Gillespie Company Shell Loading Plant in Sayreville, New Jersey. Fires and explosions continue for three days forcing massive evacuations and spreading ordnance over a wide area, pieces of which were still being found as of 2007.
- 1927 – Gutzon Borglum begins sculpting Mount Rushmore.
- 1940 – Meeting between Adolf Hitler and Benito Mussolini at the Brenner Pass.
- 1941 – Norman Rockwell's Willie Gillis character debuts on the cover of the Saturday Evening Post.
- 1943 – World War II: U.S. captures Solomon Islands.
- 1957 – Space Race: Launch of Sputnik I, the first artificial satellite to orbit the Earth.
- 1957 – Avro Arrow roll-out ceremony at Avro Canada plant in Malton, Ontario.
- 1957 – Leave It To Beaver premieres on CBS.
- 1958 – Fifth Republic of France is established.
- 1960 – Eastern Air Lines Flight 375, a Lockheed L-188 Electra, crashes after a bird strike on takeoff from Boston's Logan International Airport, killing 62 of 72 on board.
- 1963 – Hurricane Flora, kills 6,000 in Cuba and Haiti.
- 1965 – Becoming the first Pope to ever visit the United States of America and the Western hemisphere, Pope Paul VI arrives in New York.
- 1966 – Basutoland becomes independent from the United Kingdom and is renamed Lesotho.
- 1967 – Omar Ali Saifuddin III of Brunei abdicates in favour of his son, His Majesty Sultan Hassanal Bolkiah.
- 1974 – Founding of the New Democracy party in Greece.
- 1976 – Official launch of the Intercity 125 High Speed Train (HST).
- 1983 – Richard Noble sets a new land speed record of 633.468 mph (1,019 km/h), driving Thrust 2 at the Black Rock Desert of Nevada.
- 1985 – Free Software Foundation is founded in Massachusetts, United States.
- 1988 – U.S. televangelist Jim Bakker is indicted for fraud.
- 1991 – The Protocol on Environmental Protection to the Antarctic Treaty is opened for signature.
- 1992 – The Rome General Peace Accords ends a 16 year civil war in Mozambique.
- 1992 – El Al Flight 1862: an El Al Boeing 747-258F crashes into two apartment buildings in Amsterdam, killing 43 including 39 on the ground.
- 1993 – Russian Constitutional Crisis: In Moscow, tanks bombard the White House, a government building that housed the Russian parliament, while demonstrators against President Boris Yeltsin rally outside.
- 1997 – The second largest cash robbery in U.S. history occurs at the Charlotte, North Carolina office of Loomis, Fargo and Company. An FBI investigation eventually results in 24 convictions and the recovery of approximately 95% of the $17.3 million in cash which had been taken.
- 2001 – NATO confirms invocation of Article 5 of the North Atlantic Treaty.
- 2001 – Siberia Airlines Flight 1812: a Sibir Airlines Tupolev TU-154 crashes into the Black Sea after being struck by an errant Ukrainian S-200 missile. 78 people are killed.
- 2003 – Maxim restaurant suicide bombing in Haifa, Israel: 21 Israelis, Jews and Arabs, are killed, and 51 others wounded.
- 2004 – SpaceShipOne wins Ansari X Prize for private spaceflight, by being the first private craft to fly into space.
October 3
- 52 BC – Vercingetorix, leader of the Gauls, surrenders to the Romans under Julius Caesar, ending the siege and Battle of Alesia.
- 42 BC – First Battle of Philippi: Triumvirs Mark Antony and Octavian fight a decisive battle with Caesar's assassins Brutus and Cassius.
- 382 – Emperor Theodosius I concludes a peace treaty with the Goths and settles them in the Balkans in exchange for military service.
- 1283 – Dafydd ap Gruffydd, prince of Gwynedd in Wales, becomes the first nobleman executed by being hanged, drawn and quartered.
- 1574 – The Siege of Leiden is lifted by the Watergeuzen.
- 1683 – The Qing Dynasty naval commander Shi Lang reaches Taiwan (under the Kingdom of Tungning) to receive the formal surrender of Zheng Keshuang and Liu Guoxuan after the Battle of Penghu.
- 1712 – The Duke of Montrose issues a warrant for the arrest of Rob Roy MacGregor.
- 1739 – The Treaty of Nissa is signed by the Ottoman Empire and Russia at the finish of the Russian-Turkish War, 1736–1739.
- 1778 – British Captain James Cook anchors in Alaska.
- 1789 – George Washington made the first Thanksgiving Day designated by the national government of the United States of America.
- 1795 – General Napoleon Bonaparte first rises to national prominence being named to defend the French National Convention against armed counter-revolutionary rioters threatening the three year old revolutionary government.
- 1835 – The Staedtler Company is founded in Nuremberg, Germany.
- 1849 – American author Edgar Allan Poe is found delirious in a gutter in Baltimore, Maryland under mysterious circumstances; it is the last time he is seen in public before his death.
- 1863 – The last Thursday in November is declared as Thanksgiving Day by President Abraham Lincoln as are Thursdays, November 30, 1865 and November 29, 1866.
- 1872 – Bloomingdale brothers opened their first store at 938 Third Avenue, New York City.
- 1873 – Captain Jack and companions are hanged for their part in the Modoc War.
- 1908 – The Pravda newspaper is founded by Leon Trotsky, Adolph Joffe, Matvey Skobelev and other Russian exiles in Vienna.
- 1918 – King Boris III of Bulgaria accedes to the throne.
- 1919 – Cincinnati Reds pitcher Adolfo Luque becomes the 1st Latin player to appear in a World Series.
- 1929 – The Kingdom of Serbs, Croats and Slovenes is renamed to Kingdom of Yugoslavia, "Land of the South Slavs".
- 1932 – Iraq gains independence from the United Kingdom.
- 1935 – Second Italo-Abyssinian War: Italy invades Ethiopia under General de Bono.
- 1942 – Spaceflight: The first successful launch of a V-2 /A4-rocket from Test Stand VII at Peenemünde, Germany. It is the first man-made object to reach space.
- 1949 – WERD, the 1st black-owned radio station in the United States, opens in Atlanta, Georgia.
- 1950 – Korean War: The First Battle of Maryang San, primarily pitting Australian and British forces against communist China, begins.
- 1951 – The "Shot Heard 'Round the World", one of the greatest moments in Major League Baseball history, occurs when the New York Giants' Bobby Thomson hits a game winning home run in the bottom of the ninth inning off of the Brooklyn Dodgers pitcher Ralph Branca, to win the National League pennant after being down 14 games.
- 1952 – The United Kingdom successfully tests a nuclear weapon to become the world's third nuclear power.
- 1955 – The Mickey Mouse Club debuts on ABC.
- 1957 – Allen Ginsberg's Howl and Other Poems is ruled not obscene.
- 1961 – The Dick Van Dyke Show premieres on CBS-TV in the United States.
- 1962 – Project Mercury: Sigma 7 is launched from Cape Canaveral, with Astronaut Wally Schirra aboard, for a six-orbit, nine-hour flight.
- 1964 – First Buffalo Wings are made at the Anchor Bar in Buffalo, New York.
- 1981 – The Hunger Strike by Provisional Irish Republican Army and Irish National Liberation Army prisoners at the Maze Prison in Northern Ireland ends after seven months and ten deaths.
- 1985 – The Space Shuttle Atlantis makes its maiden flight. (Mission STS-51-J)
- 1986 – TASCC, a superconducting cyclotron at the Chalk River Laboratories, is officially opened.
- 1990 – Re-unification of Germany. The German Democratic Republic ceases to exist and its territory becomes part of the Federal Republic of Germany. East German citizens became part of the European Community, which later became the European Union. Now celebrated as German Unity Day.
- 1993 – Battle of Mogadishu: In an attempt to capture officials of warlord Mohamed Farrah Aidid's organisation in Mogadishu, Somalia, 18 US soldiers and about 1,000 Somalis are killed in heavy fighting.
- 1995 – O. J. Simpson is acquitted of the murders of Nicole Brown Simpson and Ronald Goldman.
- 2003 – Roy Horn of Siegfried & Roy is attacked by one of the show's tigers, canceling the show until 2009, when they rejoined the tiger that mauled Roy just six years earlier.
- 2008 – The Emergency Economic Stabilization Act of 2008 for the US financial system is signed by President Bush.
October 2
- 1187 – Siege of Jerusalem: Saladin captures Jerusalem after 88 years of Crusader rule.
- 1263 – The battle of Largs is fought between Norwegians and Scots.
- 1535 – Jacques Cartier discovers Montreal, Quebec.
- 1552 – Conquest of Kazan by Ivan the Terrible.
- 1780 – John André, British Army officer of the American Revolutionary War, is hanged as a spy by American forces.
- 1789 – George Washington sends the proposed Constitutional amendments (The United States Bill of Rights) to the States for ratification.
- 1814 – Battle of Rancagua: Spanish Royalists troops under Mariano Osorio defeated rebel Chilean forces of Bernardo O'Higgins and Jose Miguel Carrera.
- 1835 – The Texas Revolution begins with the Battle of Gonzales: Mexican soldiers attempt to disarm the people of Gonzales, Texas, but encounter stiff resistance from a hastily assembled militia.
- 1864 – American Civil War: Battle of Saltville – Union forces attack Saltville, Virginia, but are defeated by Confederate troops.
- 1889 – In Colorado, Nicholas Creede strikes it rich in silver during the last great silver boom of the American Old West.
- 1919 – U.S. President Woodrow Wilson suffers a massive stroke, leaving him partially paralyzed.
- 1924 – The Geneva Protocol is adopted as a means to strengthen the League of Nations.
- 1925 – John Logie Baird performs the first test of a working television system.
- 1928 – The "Prelature of the Holy Cross and the Work of God", commonly known as Opus Dei, is founded by Saint Josemaría Escrivá.
- 1937 – Dominican Republic strongman Rafael Trujillo orders the execution of the Haitian population living within the borderlands; approximately 20,000 are killed over the next five days.
- 1941 – World War II: In Operation Typhoon, Germany begins an all-out offensive against Moscow.
- 1944 – World War II: Nazi troops end the Warsaw Uprising.
- 1950 – Peanuts by Charles M. Schulz is first published
- 1958 – Guinea declares its independence from France.
- 1959 – The anthology series The Twilight Zone premieres on CBS television.
- 1967 – Thurgood Marshall is sworn in as the first African-American justice of United States Supreme Court.
- 1968 – A peaceful student demonstration in Mexico City culminates in the Tlatelolco massacre.
- 1970 – A plane carrying the Wichita State University football team, administrators, and supporters crashes in Colorado killing 31 people.
- 1990 – Xiamen Airlines Flight 8301 is hijacked; after landing at Guangzhou, it crashes into two airliners on the ground, killing 132 people.
- 1992 – The Carandiru Massacre takes place after a riot in the Carandiru Penitentiary in São Paulo, Brazil.
- 1996 – The Electronic Freedom of Information Act Amendments are signed by U.S. President Bill Clinton.
- 1996 – Aeroperú Flight 603, a Boeing 757, crashes into the Pacific Ocean shortly after takeoff from Lima, Peru, killing 70.
- 2001 – NATO backs U.S. military strikes following 9/11.
- 2001 – Swissair liquidates and the airline is replaced by SWISS.
- 2002 – The Beltway sniper attacks begin, extending over three weeks.
- 2005 – Ethan Allen Boating Accident: The Ethan Allen tour boat capsizes on Lake George in Upstate New York, killing twenty people.
- 2006 – Five school girls are murdered by Charles Carl Roberts in a shooting at an Amish school in Nickel Mines, Pennsylvania before Roberts commits suicide.
- 2007 – President Roh Moo-hyun of South Korea walks across the Military Demarcation Line into North Korea on his way to the second Inter-Korean Summit with North Korean leader Kim Jong Il.
