October 15 is the 288th day of the year (289th in leap years) in the Gregorian calendar. There are 77 days remaining until the end of the year.
- 533 – Byzantine general Belisarius makes his formal entry into Carthage, having conquered it from the Vandals.
- 1066 - After the Battle of Hastings, Edgar the AEtheling is proclaimed King of England, but is never crowned.
- 1529 - The Siege of Vienna ends, as the Austrians defeat the invading Ottoman Turks.
- 1552 – Khanate of Kazan is conquered by troops of Ivan Grozny.
- 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.
- 1764 – Edward Gibbon observes a group of friars singing in the ruined Temple of Jupiter in Rome, which inspires him to begin work on The History of the Decline and Fall of the Roman Empire.
- 1783 - The Montgolfier brothers' hot-air balloon marks the first human flight in this mode of transport, by Jean-Jacques Pilatre de Rozier.
- 1793 – Marie Antoinette is sentenced to death, being executed the next day.
- 1815 – Napoleon I of France begins his exile on St. Helena in the Atlantic Ocean.
- 1863 – American Civil War: The first successful submarine, the CSS Hunley sinks during a test, killing its inventor.
- 1864 - American Civil War: Battle of Glasgow, Glasgow, Missouri. The town surrenders its garrison to the Confederacy.
- 1878 – The Edison Electric Company begins operation.
- 1880 – Mexican soldiers kill Victorio, one of the greatest Apache military strategists.
- 1883 – The Supreme Court of the United States declares part of the Civil Rights Act of 1875 to be unconstitutional.
- 1888 - Investigators receives the "From Hell" letter, believed to have been written by the unidentified serial killer known as Jack the Ripper.
- 1894 – Alfred Dreyfus is arrested for spying – Dreyfus affair begins.
- 1904 – The Russian Baltic Fleet leaves Reval, Estonia for Port Arthur, Manchuria during the Russo-Japanese War.
- 1917 – World War I: At Vincennes outside of Paris, Dutch dancer Mata Hari is executed by firing squad for spying for Germany.
- 1928 - Airship Graf Zeppelin completes its first flight across the Atlantic Ocean when it lands at Lakehurst, New Jersey.
- 1932 – Tata Airlines (later to become Air India) makes its first flight.
- 1934 - The Soviet Republic of China collapses.
- 1939 – The New York Municipal Airport (later renamed La Guardia Airport) is dedicated.
- 1940 – The Great Dictator, a satiric social commentary movie by and starring Charlie Chaplin, is released.
- 1944 - The Arrow Cross Party, allied to Adolf Hitler's Nazi Party, takes power in Hungary.
- 1945 – World War II: Former premier of Vichy France, Pierre Laval, is executed by firing squad for treason.
- 1946 – Nuremberg Trials: Founder of the Gestapo and recently convicted Nazi war criminal, Hermann Göring, poisons himself hours before his scheduled execution.
- 1951 – Television sitcom I Love Lucy premieres.
- 1953 – British nuclear test Totem 1 detonated at Emu Field, South Australia.
- 1954 - Hurricane Hazel strikes the eastern United States, killing 95 people.
- 1956 - Fortran, the first modern computer language, is first shared in the coding community.
- 1962 – Cuban Missile Crisis: A stand-off ensues between the United States and the Soviet Union over Soviet nuclear weapons in Cuba.
- 1963 - German Federal Chancellor Konrad Adenauer officially resigns.
- 1965 – Vietnam War: The National Coordinating Committee to End the War in Vietnam stages the first public burning of a draft card in the United States.
- 1966 – US President Lyndon B. Johnson signs a bill creating the United States Department of Transportation.
- 1969 – Vietnam War: Hundreds of thousands of people take part in National Moratorium antiwar demonstrations across the United States.
- 1970 – Thirty-five construction workers are killed when a section of the new West Gate Bridge in Melbourne collapses.
- 1979 - A military junta takes over in El Salvador, after the overthrow of President Carlos Humberto Romero.
- 1981 – Professional cheerleader Krazy George Henderson leads what is thought to be the first audience wave in Oakland, California.
- 1982 - The first 400-year cycle of the Gregorian calendar ends. This date is therefore on exactly the same week-day as the same date in 1582 (the day it was first introduced).
- 1987 – The Great Storm of 1987 hits France and England in the night to October 16.
- 1989 – Wayne Gretzky becomes the all-time leading points scorer in the NHL.
- 1990 – Soviet Union leader Mikhail Gorbachev is given the Nobel Peace Prize for his efforts to lessen Cold War tensions and open up his nation.
- 1991 – Following a bitter confirmation hearing that involved allegations of sexual misconduct, the United States Senate votes to confirm Judge Clarence Thomas to the Supreme Court of the United States.
- 1992 – In Russia, Andrei Chikatilo is found guilty of 52 serial murders.
- 1993 - Nelson Mandela and F. W. de Klerk win the Nobel Peace Prize.
- 1995 – Saddam Hussein gains 99.96% of votes in Iraq's presidential elections.
- 1997 – The first supersonic land speed record is set by the ThrustSSC team from the United Kingdom.
- 1997 – The Cassini probe launches from Cape Canaveral, Florida on its way to Saturn.
- 70 BC – Virgil, Roman poet (d. 19 BC)
- 1265 - Temur Khan, Emperor Chengzong of Yuan-China (d. 1307)
- 1471 – Konrad Mutian, German humanist (d. 1526)
- 1542 - Akbar the Great, Mughal Emperor of India (d. 1605)
- 1607 - Madeleine de Scudéry, French writer (d. 1701)
- 1608 – Evangelista Torricelli, Italian physicist (d. 1647)
- 1686 - Allan Ramsay, Scottish poet (d. 1758)
- 1701 - Marie-Marguerite d'Youville, Canadian nun and saint (d. 1771)
- 1711 - Elisabeth Teresa of Lorraine, Queen of Sardinia (d. 1741)
- 1762 - Samuel Adams Holyoake, American composer (d. 1820)
- 1784 - Thomas Robert Bugeaud, Marshal of France (d. 1849)
- 1785 – José Miguel Carrera, Chilean general (d. 1821)
- 1795 – Frederick William IV of Prussia (d. 1861)
- 1801 - Seabury Ford, 20th Governor of Ohio (d. 1855)
- 1802 - Louis-Eugene de Cavaignac, French general (d. 1857)
- 1814 – Mikhail Lermontov, Russian writer (d. 1841)
- 1818 - Alexander Dreyschock, Bohemian composer (d. 1869)
- 1825 – Marie of Prussia (d. 1889)
- 1829 – Asaph Hall, American astronomer (d. 1907)
- 1831 - Horace Austin, Governor of Minnesota (d. 1905)
- 1836 – James Tissot, French artist (d. 1902)
- 1840 - August Mau, German archaeologist (d. 1909)
- 1844 – Friedrich Nietzsche, German philosopher (d. 1900)
- 1852 - Yamamoto Gonnohyoe, Japanese admiral and politician (d. 1933)
- 1858 – John L. Sullivan, boxing champion (d. 1918)
- 1869 - Francisco Largo Caballero, Spanish politician (d. 1946)
- 1872 – Wilhelm Miklas, President of Austria (d. 1956)
- 1872 - August Nilsson, Swedish athlete (d. 1921)
- 1872 - Edith Wilson, First Lady of the United States (d. 1961)
- 1874 - Alfred, Hereditary Prince of Saxe-Coburg and Gotha (d. 1899)
- 1878 - Paul Reynaud, French politician (d. 1966)
- 1879 - Jane Darwell, American actress (d. 1967)
- 1881 – P. G. Wodehouse, British comic novelist (d. 1975)
- 1885 – Johannes Sveinsson Kjarval, Icelandic painter (d. 1972)
- 1890 - Homer M. Adkins, Governor of Arkansas (d. 1964)
- 1893 – King Carol II of Romania (d. 1953)
- 1894 – Moshe Sharett, second Prime Minister of Israel (d. 1965)
- 1897 - Johannes Sikkar, Estonian soldier and politician (d. 1960)
- 1898 – Boughera El Ouafi, Algerian athlete (d. 1951)
- 1900 – Mervyn LeRoy, movie director (d. 1987)
- 1905 – Angelo Schiavio, Italian footballer (d. 1990)
- 1906 – Hiram Leong Fong, Hawaiian politician (d. 2004)
- 1907 – Varian Fry, rescuer of Jewish and other intellectuals from Marseilles in 1940 (d. 1987)
- 1908 – John Kenneth Galbraith, Canadian economist (d. 2006)
- 1909 - Jesse Leonard Greenstein, American astronomer (d. 2002)
- 1909 – Robert Trout, reporter (d. 2000)
- 1911 - John S. McKiernan, Governor of Rhode Island (d. 1997)
- 1913 - Xi Zhongxun, Chinese Communist revolutionary and politician (d. 2002)
- 1914 – Mohammed Zahir Shah, King of Afghanistan (d. 2007)
- 1915 – Yitzhak Shamir, Israeli politician and Prime Minister of Israel (d. 2012)
- 1916 - Hassan Gouled Aptidon, 1st President of Djibouti (d. 2006)
- 1917 – Arthur Schlesinger Jr., American political commentator and writer (d. 2007)
- 1917 – Jan Miner, American actress (d. 2004)
- 1919 - Malcolm Ross, American balloonist and physicist (d. 1985)
- 1920 – Mario Puzo, American novelist (d. 1999)
- 1920 – Chris Economaki, American Indianapolis 500 reporter (d. 2012)
- 1920 - Heinz Barth, German SS officer and war criminal (d. 2007)
- 1923 – Italo Calvino. Italian writer (d. 1985)
- 1924 – Lee Iacocca, industrialist
- 1924 – José Quintero, stage director
- 1924 – Mark Lenard, actor (d. 1996)
- 1926 – Michel Foucault, French philosopher (d. 1984)
- 1926 – Evan Hunter (Ed McBain, Curt Cannon), American writer (d. 2005)
- 1926 – Jean Peters, American actress (d. 2000)
- 1926 – Karl Richter, German conductor (d. 1981)
- 1926 - Agustin Garcia Calvo, Spanish philosopher (d. 2012)
- 1927 - Jeannette Charles, English actress
- 1927 - Bill Henry, American baseball player (d. 2014)
- 1927 - B. S. Abdur Rahman, Indian entrepreneur (d. 2015)
- 1930 - FM-2030, Iranian philosopher (d. 2000)
- 1930 - Ned McWherter, Governor of Tennessee (d. 2011)
- 1931 – Avul Pakir Jainulabdeen Abdul Kalam, Indian scientist and former President of India (d. 2015)
- 1931 - Pauline Perry, Baroness Perry of Southwark, English academic and politician
- 1935 – Bobby Joe Morrow, American athlete
- 1935 - Dick McTaggart, British boxer
- 1935 - Maria Teresa Mirabal, Dominican activist (d. 1960)
- 1937 – Barry McGuire, singer
- 1937 - Linda Lavin, American actress, singer, director and producer
- 1938 – Fela Kuti, Nigerian musician (d. 1997)
- 1939 - Telesphore Toppo, Indian cardinal
- 1939 - Carmelo Bossi, Italian boxer (d. 2014)
- 1939 - Anna Maria Gherardi, Italian actress (d. 2014)
- 1940 – Peter C. Doherty, Australian immunologist
- 1940 – Benno Ohnesorg, German student (d. 1967)
- 1942 – Penny Marshall, actress, comedienne, movie director
- 1942 - Eric Charden, French singer (d. 2012)
- 1943 - John F. Street, American politician
- 1943 - Stanley Fischer, American economist and teacher
- 1944 – Sali Berisha, Albanian politician
- 1944 – David Trimble, Northern Irish politician, Nobel Peace Prize winner
- 1945 – Jim Palmer, American baseball player
- 1945 - Neophyte of Bulgaria, Bulgarian patriarch
- 1945 - Antonio Cañizares Llovera, Spanish cardinal
- 1946 – Richard Carpenter, singer, pianist, composer (Carpenters)
- 1946 - Stewart Stevenson, Scottish politician
- 1948 – Chris de Burgh, Irish singer
- 1948 - Renato Corona, Filipino jurist (d. 2016)
- 1950 - Candida Royalle, American pornographic actress, director and producer (d. 2015)
- 1951 - Roscoe Tanner, American tennis player
- 1951 - Abdel Moneim Aboul Fotouh, Egyptian politician
- 1953 – Tito Jackson, American musician (Jackson 5)
- 1953 - Günther Oettinger, German politician
- 1954 - Princess Friederike of Hanover
- 1954 - Jere Burns, American actor
- 1955 - Tanya Roberts, American actress (d. 2021)
- 1955 - Kulbir Bhaura, Indian field hockey player
- 1956 - Soraya Post, Swedish politician
- 1956 - Jaime David Fernandez Mirabal, 36th Vice President of the Dominican Republic
- 1957 – Mira Nair, Indian director
- 1957 - Stacy Peralta, American director
- 1959 – Sarah Ferguson, Duchess of York
- 1959 – Emeril Lagasse, American chef
- 1959 – Todd Solondz, director
- 1964 – Roberto Vittori, Italian astronaut
- 1966 - Jorge Campos, Mexican footballer
- 1966 - Dave Stead, English musician (Beautiful South)
- 1966 - Dougie Vipond, Scottish broadcaster and drummer (Deacon Blue)
- 1968 – Jyrki 69, Finnish musician
- 1968 – Didier Deschamps, French footballer
- 1968 - Vanessa Marcil, American actress
- 1969 – Dominic West, British actor
- 1969 - Vitor Baia, Portuguese footballer
- 1970 – Eric Benét, singer
- 1971 – Andy Cole, British footballer
- 1971 - Niko Kovac, Croatian footballer and coach
- 1972 – Sandra Kim, Belgian singer, Eurovision Song Contest winner
- 1972 - Fred Hoiberg, American basketball player
- 1974 - Bianca Rinaldi, Brazilian actress
- 1975 – Ginuwine, American singer
- 1977 – David Trezeguet, French footballer
- 1979 – Paul Robinson, English footballer
- 1979 – Maris Verpakovskis, Latvian footballer
- 1981 – Elena Dementieva, Russian tennis player
- 1981 - Keyshia Cole, American singer
- 1982 - Sachiko Yamada, Japanese swimmer
- 1983 - Holly Montag, American television personality
- 1983 - Bruno Senna, Brazilian racing driver
- 1983 – Andreas Ivanschitz, Austrian footballer
- 1986 - Lee Donghae, South Korean singer-songwriter and actress
- 1986 - Carlo Janka, Swiss skier
- 1987 - Chantal Strand, Canadian voice actress and singer
- 1988 – Mesut Oezil, German footballer
- 1989 - Anthony Joshua, English boxer
- 1989 - Fedez, Italian rapper and singer
- 1990 - Jeon Ji-yoon, South Korean singer and actress
- 1990 - Kiko Mizuhara, American-Japanese model, actress and singer
- 1995 - Billy Unger, American actor
- 1996 - Zelo, South Korean rapper and dancer
- 1999 - Bailee Madison, American actress
- 2005 – Prince Christian of Denmark
- 412 - Pope Theophilus of Alexandria
- 767 – Constantine II, Patriarch of Constantinople (executed)
- 898 - Lambert, Holy Roman Emperor
- 1002 – Otto-Henry, Duke of Burgundy (b. 949)
- 1174 - Petronilla of Aragon (b. 1135)
- 1326 - Walter de Stapledon, English bishop (b. 1261)
- 1389 – Pope Urban VI (b. 1318)
- 1564 - Andreas Vesalius, Flemish anatomist (b. 1514)
- 1582 – Saint Teresa of Avila, Spanish Carmelite nun and poet (b. 1515)
- 1715 - Humphry Ditton, English mathematician (b. 1675)
- 1811 – Sir Nathaniel Dance-Holland, English painter (b. 1735)
- 1817 - Tadeusz Kosciuszko, Lithuanian-Polish military figure (b. 1746)
- 1819 - Sergey Vyazmitinov, Russian general and statesman (b. 1744)
- 1837 - Ivan Dimitriev, Russian poet and statesman (b. 1760)
- 1865 - Andrés Bello, Venezuelan polymath (b. 1781)
- 1880 – Victorio, Apache leader
- 1891 – Gilbert Arthur a Beckett, British writer (b. 1837)
- 1900 – Zdenek Fibich, Czech composer (b. 1850)
- 1904 - George, King of Saxony (b. 1832)
- 1917 – Mata Hari, Dutch exotic dancer and spy (b. 1867)
- 1918 - Sai Baba of Shirdi, Indian guru and national saint of India (b. 1838)
- 1933 - Nitobe Inazo, Japanese diplomat (b. 1862)
- 1934 – Raymond Poincaré, French statesman (b. 1860)
- 1945 – Pierre Laval, premier of Vichy France (b. 1860)
- 1946 – Hermann Göring, German air force commander (b. 1893)
- 1948 - Edythe Chapman, American actress (b. 1863)
- 1955 - Fumio Hayasaka, Japanese composer (b. 1914)
- 1959 - Stepan Bandera, Ukrainian politician (b. 1909)
- 1960 - Clara Kimball Young, American actress and producer (b. 1890)
- 1964 – Cole Porter, American composer (b. 1891)
- 1965 – Abraham Fraenkel, Israeli mathematician (b. 1891)
- 1976 - Carlo Gambino, Italian-American crime boss (b. 1902)
- 1980 - Mikhail Lavrentyov, Russian physicist and mathematician (b. 1900)
- 1980 - Apostolis Nikolaidis, Greek footballer and volleyball player (b. 1896)
- 1987 – Thomas Sankara, Burkina Faso politician (b. 1949)
- 1988 – Kaikhosru Shapurji Sorabji, Indian composer and classical pianist (b. 1892)
- 1990 - Delphine Seyrig, French actress (b. 1932)
- 1994 - Sarah Kofman, French philosopher (b. 1934)
- 1995 - Marco Campos, Brazilian racing driver (b. 1976)
- 1998 - Colette Darfeuil, French actress (b. 1906)
- 2000 – Konrad Emil Bloch, German-American biochemist (b. 1912)
- 2001 – Zhang Xueliang, Chinese warlord and military figure (b. 1901)
- 2003 – Ben Metcalfe, environmental activist (b. 1919)
- 2005 - Jason Collier, American basketball player (b. 1977)
- 2011 - Betty Driver, English actress (b. 1920)
- 2012 - Norodom Sihanouk, King of Cambodia (b. 1922)
- 2012 - Claude Cheysson, French politician (b. 1920)
- 2013 - Rudolf Friedrich, Swiss politician (b. 1923)
- 2013 - Hans Riegel, German businessman (b. 1923)
- 2014 - Marie Dubois, French actress (b. 1937)
- 2014 - Giovanni Reale, Italian historian and philosopher (b. 1931)
- 2014 - Robert Tiernan, American politician (b. 1929)
- 2015 - Kenneth D. Taylor, Canadian diplomat (b. 1934)
- 2015 - Nate Huffman, American basketball player (b. 1975)
- 2015 - Sergei Filippenkov, Russian footballer (b. 1971)
- 2015 - Larry N. Vanderhoef, American biochemist (b. 1941)
- 2015 - Neill Sheridan, American baseball player (b. 1921)