Today is 12 December 2017, and this is some of what happened.
- Battle of Nineveh: A Byzantine army under Emperor Heraclius defeats Emperor Khosrau II's Persian forces, commanded by General Rhahzadh.
- First Crusade: Siege of Ma'arrat al-Numan: Crusaders breach the town's walls and massacre about 20,000 inhabitants. After finding themselves with insufficient food, they reportedly resort to cannibalism.
- Mary of Enghien sells the lordship of Argos and Nauplia to the Republic of Venice.
- The Order of the Dragon a monarchical chivalric order is created by Sigismund of Luxembourg, then King of Hungary.
- American Revolutionary War: Second Battle of Ushant: A British fleet led by HMS Victory defeats a French fleet.
- Pennsylvania becomes the second state to ratify the United States Constitution, five days after Delaware became the first.
- American Civil War: USS Cairo sinks on the Yazoo River, becoming the first armored ship to be sunk by an electrically detonated mine.
- Joseph H. Rainey of South Carolina becomes the second black U.S. congressman, the first being Hiram Revels.
- Belo Horizonte, the first planned city in Brazil, is founded.
- Guglielmo Marconi receives the first transatlantic radio signal (the letter "S" [***] in Morse Code), at Signal Hill in St John's, Newfoundland.
- Delhi replaces Calcutta as the capital of India.
- King George V of the United Kingdom and Mary of Teck are enthroned as Emperor and Empress of India.
- President of the Republic of China, Yuan Shikai, announces his intention to reinstate the monarchy and proclaim himself Emperor of China.
- In Nebraska, Father Edward J. Flanagan founds Boys Town as a farm village for wayward boys.
- The Flag of Estonia is raised atop the Pikk Hermann for the first time.
- The Majlis of Iran votes to crown Reza Khan as the new Shah of Iran, starting the Pahlavi dynasty.
- Lebensborn Project, a Nazi reproduction program, is founded by Heinrich Himmler.
- Xi'an Incident: The Generalissimo of the Republic of China, Chiang Kai-shek, is kidnapped by Zhang Xueliang.
- Second Sino-Japanese War: USS Panay incident: Japanese aircraft bomb and sink U.S. gunboat USS Panay on the Yangtze river in China.
- Winter War: Battle of Tolvajärvi: Finnish forces defeat those of the Soviet Union in their first major victory of the conflict.
- HMS Duchess sinks after a collision with HMS Barham off the coast of Scotland with the loss of 124 men.
- World War II: Approximately 70 people are killed in the Marples Hotel, Fitzalan Square, Sheffield, as a result of a German air raid.
- World War II: Fifty-four Japanese A6M Zero fighters raid Batangas Field, Philippines. Jesús Villamor and four Filipino fighter pilots fend them off; César Basa is killed.
- World War II: The United Kingdom declares war on Bulgaria. Hungary and Romania declare war on the United States. India declares war on Japan.
- Adolf Hitler declares the imminent extermination of the Jews at a meeting in the Reich Chancellery
- World War II: German troops begin Operation Winter Storm, an attempt to relieve encircled Axis forces during the Battle of Stalingrad.
- A fire in a hostel in St. John's, Newfoundland, kills 100 people.
- A fire at a New York City ice plant spreads to a nearby tenement, killing 37 people.
- Malayan Emergency: Batang Kali massacre: Fourteen members of the Scots Guards stationed in Malaya allegedly massacre 24 unarmed civilians and set fire to the village.
- Paula Ackerman, the first woman appointed to perform rabbinical functions in the United States, leads the congregation in her first services.
- Beginning of the Irish Republican Army's "Border Campaign".
- United Nations Security Council Resolution 121 relating to Japan on membership in United Nations.
- Guinea joins the United Nations.
- Kenya gains its independence from the United Kingdom.
- Prime Minister Jomo Kenyatta becomes the first President of the Republic of Kenya.
- Years of Lead: Piazza Fontana bombing: The offices of Banca Nazionale dell'Agricoltura in Piazza Fontana, Milan, are bombed.
- Coup d'état of December Twelfth: South Korean Army Major General Chun Doo-hwan orders the arrest of Army Chief of Staff General Jeong Seung-hwa without authorization from President Choi Kyu-ha, alleging involvement in the assassination of ex-President Park Chung-hee.
- President of Pakistan Muhammad Zia-ul-Haq confers Nishan-e-Imtiaz on Nobel laureate Dr Abdus Salam.
- The unrecognised state of Zimbabwe-Rhodesia returns to British control and resumes using the name Southern Rhodesia.
- The 8.2 Mw Tumaco earthquake shakes Colombia and Ecuador with a maximum Mercalli intensity of IX (Violent), killing 300-600, and generating a large tsunami.
- The Australian Labor government led by Prime Minister Bob Hawke and Treasurer Paul Keating floats the Australian dollar.
- Maaouya Ould Sid'Ahmed Taya becomes the third president of Mauritania after a coup d'état against Mohamed Khouna Ould Haidalla while the latter is attending a summit.
- Arrow Air Flight 1285, a McDonnell Douglas DC-8, crashes after takeoff in Gander, Newfoundland, killing all 256 people on board, including 236 members of the United States Army's 101st Airborne Division.
- The Clapham Junction rail crash kills thirty-five and injures hundreds after two collisions of three commuter trains—one of the worst train crashes in the United Kingdom.
- The Russian Federation gains independence from the USSR.
- The United States Supreme Court releases its decision in Bush v. Gore.
- Albert II, Duke of Austria (died 1358)
- Álvaro de Bazán, 1st Marquis of Santa Cruz, Spanish admiral (died 1588)
- Anne of Denmark (died 1619)
- Basil of Ostrog, Serbian monk and saint (died 1671)
- Lodovico Giustini, Italian pianist and composer (died 1743)
- Prince Charles Alexander of Lorraine (died 1780)
- Samuel Hood, 1st Viscount Hood, English admiral and politician (died 1816)
- Erasmus Darwin, English physician and poet (died 1802)
- John Jay, American jurist and politician, 1st Chief Justice of the United States (died 1829)
- Nikolay Karamzin, Russian poet and historian (died 1826)
- Madeleine Sophie Barat, French nun and saint, founded the Society of the Sacred Heart (died 1865)
- William L. Marcy, American lawyer, judge, and politician, 21st United States Secretary of State (died 1857)
- Marie Louise, Duchess of Parma (died 1847)
- Alexander Ypsilantis, Greek-Russian general and politician, Military ruler of Moldavia (died 1828)
- Karl Bryullov, Russian painter (died 1852)
- William Lloyd Garrison, American journalist and activist, founded The Liberator (died 1879)
- Henry Wells, American businessman, co-founded Wells Fargo and American Express (died 1878)
- Stand Watie, American general (died 1871)
- John Sandfield Macdonald, Canadian lawyer and politician, 1st Premier of Ontario (died 1872)
- Juan Prim, 1st Marquis of los Castillejos, Spanish general and politician, Prime Minister of Spain (died 1870)
- Gustave Flaubert, French author and playwright (died 1880)
- Adolf Bötticher, German journalist and historian (died 1901)
- Bruce Price, American architect, designed the American Surety Building and Bank of the Metropolis (died 1903)
- William Kissam Vanderbilt, American businessman and horse breeder (died 1920)
- J. Bruce Ismay, English businessman (died 1937)
- Edvard Munch, Norwegian painter and illustrator (died 1944)
- Paul Elmer More, American journalist, author, and critic (died 1937)
- Alfred Werner, Swiss chemist and academic, Nobel Prize laureate (died 1919)
- Walter Benona Sharp, American businessman, co-founded Hughes Tool Company (died 1912)
- Gerd von Rundstedt, German field marshal (died 1953)
- Alvin Kraenzlein, American hurdler and runner (died 1928)
- Harry Warner, Polish-American businessman, co-founded Warner Bros. (died 1958)
- Ioannis Demestichas, Greek admiral and politician (died 1960)
- Zinaida Serebriakova, Ukrainian-French painter (died 1967)
- Kurt Atterberg, Swedish composer and engineer (died 1974)
- Milko Kos, Slovenian historian and academic (died 1972)
- Edward G. Robinson, Romanian-American actor and singer (died 1973)
- Sammy Davis, Sr., American actor and dancer (died 1988)
- Harald Kaarmann, Estonian footballer (died 1942)
- Adele Dunlap, American educator
- Koloman Sokol, Slovak-American painter and illustrator (died 2003)
- Dagmar Nordstrom, American singer-songwriter and pianist (Nordstrom Sisters) (died 1976)
- Nicolas de Gunzburg, French-American banker, journalist, and actor (died 1981)
- Manès Sperber, Austrian-French psychologist and author (died 1984)
- Vasily Grossman, Russian journalist and author (died 1964)
- Roy Douglas, English pianist and composer (died 2015)
- Gustav Ernesaks, Estonian composer and conductor (died 1993)
- Hans Keilson, German-Dutch psychologist, author, and poet (died 2011)
- Karen Morley, American actress and singer (died 2003)
- Boun Oum, Laotian politician, 5th Prime Minister of Laos (died 1980)
- Patrick O'Brian, English author and translator (died 2000)
- Frank Sinatra, American singer, actor, and producer (died 1998)
- James Wall, American actor and manager (died 2010)
- Joe Williams, American singer and pianist (died 1999)
- Olivia Barclay, English astrologer and author (died 2001)
- Dan DeCarlo, American soldier and illustrator (died 2001)
- born born Nimbalkar, Indian cricketer (died 2012)
- Josef Dolelal, Czech race walker (died 1999)
- Fred Kida, American illustrator (died 2014)
- Christian Dotremont, Belgian painter and poet (died 1979)
- Bob Barker, American game show host and producer
- Ken Kavanagh, Australian race car driver and motorcycle racer
- Ray Cordeiro, Hong Kong radio and television host
- Ed Koch, American lawyer, judge, and politician, 105th Mayor of New York City (died 2013)
- Vladimir Shainsky, Ukrainian-Russian pianist and composer
- Ahmad Shamloo, Iranian journalist and poet (died 2000)
- Robert Noyce, American inventor and businessman, co-founded the Intel Corporation (died 1990)
- Chinghiz Aitmatov, Kyrgyzstani diplomat and author (died 2008)
- Helen Frankenthaler, American painter and academic (died 2011)
- Ernst-Hugo Järegård, Swedish actor (died 1998)
- Toshiko Akiyoshi, Japanese pianist and composer (Toshiko Akiyoshi - Lew Tabackin Big Band)
- John Osborne, English playwright and screenwriter (died 1994)
- Bill Beutel, American journalist (died 2006)
- Silvio Santos, Brazilian television host and businessman, founded Sistema Brasileiro de Televisão
- Lionel Blair, English actor, dancer, and choreographer
- Bob Pettit, American basketball player and coach
- Christa Stubnick, German sprinter
- Miguel de la Madrid, Mexican lawyer and politician, 52nd President of Mexico (died 2012)
- John Wise, Canadian farmer and politician, 23rd Minister of Agriculture (died 2013)
- Denise Coffey, English actress and director
- Michael Jeffery, Australian general and politician, 24th Governor-General of Australia
- Philip Ledger, English pianist, composer, and academic (died 2012)
- Buford Pusser, American police officer (died 1974)
- Connie Francis, American singer and actress
- Sharad Pawar, Indian politician, Indian Minister of Agriculture
- Dionne Warwick, American singer and actress
- Tim Hauser, American singer (The Manhattan Transfer) (died 2014)
- Fatma Girik, Turkish actress and politician
- Morris Sadek, Egyptian-American lawyer and activist
- Brough Scott, English jockey and journalist
- Vassilis Alexakis, Greek-French author and translator
- Dickey Betts, American singer-songwriter and guitarist (The Allman Brothers Band)
- Sadeq Tabatabaei, Iranian journalist and politician (died 2015)
- Grover Washington, Jr., American singer-songwriter, saxophonist, and producer (died 1999)
- Jean Doré, Canadian lawyer and politician, 39th Mayor of Montreal (died 2015)
- Cara Duff-MacCormick, Canadian actress
- Rob Tyner, American singer-songwriter and bass player (MC5) (died 1991)
- Portia Simpson-Miller, Jamaican politician, 7th Prime Minister of Jamaica
- Tony Williams, American drummer, composer, and producer (The Tony Williams Lifetime) (died 1997)
- Will Alsop, English architect and academic, designed the Cardiff Bay Visitor Centre
- Wings Hauser, American actor, director, and screenwriter
- Chris Mullin, English journalist and politician
- Gopinath Munde, Indian lawyer and politician, 3rd Deputy Chief Minister of Maharashtra (died 2014)
- Bill Nighy, English actor
- Marc Ravalomanana, Malagasy businessman and politician, President of Madagascar
- Rajinikanth, Indian actor, producer, and screenwriter
- Pedro Ferriz de Con, Mexican journalist
- Heiner Flassbeck, German economist and academic
- Gorman Thomas, American baseball player
- Billy Smith, Canadian ice hockey player, coach, and manager
- Rehman Malik, Pakistani politician, Pakistani Minister of Interior
- Herb Dhaliwal, Indian-Canadian businessman and politician, 3rd Canadian Minister of Natural Resources
- Sarah Douglas, English actress
- Helen Dunmore, English poet and author
- Cathy Rigby, American gymnast and actress
- Martin Ferguson, Australian lawyer and politician
- Bruce Kulick, American guitarist and songwriter (Kiss, Grand Funk Railroad, Blackjack, Union, and Eric Singer Project)
- Rafael Septién, Mexican-American football player
- Hemant Karkare, Indian police officer (died 2008)
- Gianna Angelopoulos-Daskalaki, Greek businesswoman
- Eddy Schepers, Belgian cyclist
- Stephen Smith, Australian lawyer and politician, 53rd Australian Minister of Defence
- Johan van der Velde, Dutch cyclist
- Sheila E., American singer-songwriter, drummer, and actress
- Jasper Conran, English fashion designer
- Martina Hellmann, German discus thrower
- Andrey Perlov, Russian race walker
- Tracy Austin, American tennis player and sportscaster
- Arturo Barrios, Mexican-American runner
- Peter Bergen, American-English journalist and author
- Mike Golic, American football player and radio host
- Ulrike Tillmann, German mathematician and academic
- Eduardo Castro Luque, Mexican businessman and politician (died 2012)
- Reeta Chakrabarti, English journalist
- Haywood Jeffires, American football player and coach
- Royce Gracie, Brazilian-American mixed martial artist and actor
- Ian Paisley, Jr., Northern Irish politician
- Lydia Zimmermann, Spanish actress and director
- Yuzo Koshiro, Japanese composer and producer
- John Randle, American football player
- Rory Kennedy, American director and producer
- Laurie Williams, Jamaican cricketer (died 2002)
- Sophie Kinsella, English author and educator
- Wilfred Kirochi, Kenyan runner
- Fiona May, English-Italian long jumper
- Michael Möllenbeck, German discus thrower
- Carrie Westcott, American model and actress
- Mädchen Amick, American actress
- Jennifer Connelly, American actress
- Regina Hall, American actress
- Sammy Korir, Kenyan runner
- Nicky Eaden, English footballer and coach
- Wilson Kipketer, Kenyan-Danish runner
- Georgios Theodoridis, Greek sprinter
- Hank Williams III, American singer-songwriter and guitarist (Assjack, Superjoint Ritual, and Arson Anthem)
- Gary Breen, English-Irish footballer and manager
- Tony Hsieh, American businessman, founded LinkExchange
- Walter Otta, Argentinian footballer
- Bernard Lagat, Kenyan-American runner
- Nolberto Solano, Peruvian footballer and manager
- Mayim Bialik, American actress
- Wesley Charles, Vincentian footballer
- Craig Moore, Australian footballer and manager
- Houko Kuwashima, Japanese voice actress and singer
- Dan Hawkins, English guitarist, songwriter, and producer (The Darkness and Stone Gods)
- Lloyd Owusu, Ghanaian footballer
- Asaka Seto, Japanese actress
- Yoel Hernández, Cuban hurdler
- Orlando Hudson, American baseball player
- Dean Macey, English decathlete and bobsledder
- Colin White, Canadian ice hockey player
- Gbenga Akinnagbe, American actor and screenwriter
- Garrett Atkins, American baseball player
- Nate Clements, American football player
- John Salmons, American basketball player
- Dejene Berhanu, Ethiopian runner (died 2010)
- Dorin Goian, Romanian footballer
- Berkant Göktan, Turkish-German footballer
- Ronnie Brown, American football player
- Jeret Peterson, American skier (died 2011)
- Pedro Ríos, Spanish footballer
- Yuvraj Singh, Indian cricketer
- Stephen Warnock, English footballer
- Lim "NesTea" Jae-duk, South Korean gamer
- Dmitry Tursunov, Russian tennis player
- Daniel Agger, Danish footballer
- Daniel Merrett, Australian footballer
- Pat Calathes, Greek-American basketball player
- Chris Jennings, American football player
- David Veikune, American football player
- Giannis Zaradoukas, Greek footballer
- Daddy Birori, Rwandan footballer
- Përparim Hetemaj, Finnish footballer
- Lee Qri, South Korean singer, dancer, and actress (T-ara and QBS)
- T. J. Ward, American football player
- Marte Eberson, Norwegian keyboard player and composer (Morning Has Occurred and Highasakite)
- Hahm Eun-Jung, South Korean singer, dancer, and actress (T-ara and T-ara N4)
- Seungri, South Korean singer-songwriter, dancer, and actor (Big Bang)
- Nixon Chepseba, Kenyan runner
- Victor Moses, Nigerian footballer
- Zeli Ismail, English footballer
- Mitchell Pinnock, English footballer
- Carloman II, Frankish king (born 866)
- Maimonides, Egyptian religious scholar, philosopher and physician (born 1135)
- Geoffrey, English archbishop and politician, Lord Chancellor of Great Britain (born 1152)
- Philip II, Metropolitan of Moscow (born 1507)
- Stephen Báthory, Polish king (born 1533)
- John Pell, English mathematician and linguist (born 1610)
- Henry St John, 1st Viscount Bolingbroke, English philosopher and politician, Secretary at War (born 1678)
- Johann Christoph Gottsched, German philosopher, author, and critic (born 1700)
- Charles Gray, English lawyer and politician (born 1696)
- John Ponsonby, Irish lawyer and politician (born 1713)
- Mikhail Shcherbatov, Russian historian and philosopher (born 1733)
- Meshullam Feivush Heller, Ukrainian author (born 1742)
- Tekle Giyorgis I, Ethiopian emperor (born 1751)
- William I of the Netherlands (born 1772)
- Jacques Viger, Canadian archeologist and politician, 1st Mayor of Montreal (born 1787)
- Robert Browning, English poet and playwright (born 1812)
- Viktor Bunyakovsky, Ukrainian-Russian mathematician and theorist (born 1804)
- John Sparrow David Thompson, Canadian lawyer, judge, and politician, 4th Prime Minister of Canada (born 1845)
- Menelik II, Ethiopian emperor (born 1844)
- Henrietta Swan Leavitt, American astronomer and academic (born 1868)
- Raymond Radiguet, French author and poet (born 1903)
- Alexander Parvus, Russian-German theorist and politician (born 1867)
- Jean Richepin, French author, poet, and playwright (born 1849)
- Charles Goodnight, American cattle rancher (born 1836)
- Thorleif Haug, Norwegian skier (born 1894)
- Douglas Fairbanks, American actor, producer, and screenwriter (born 1883)
- César Basa, Filipino lieutenant and pilot (born 1915)
- Mildred Bailey, American singer (born 1907)
- Albert Walsh, Canadian lawyer and politician, 1st Lieutenant Governor of Newfoundland (born 1900)
- Maithili Sharan Gupt, Indian poet and playwright (born 1866)
- William Rootes, 1st Baron Rootes, English businessman, founded Rootes Group (born 1894)
- Sailor Young. English cricketer (born 1876)
- Karl Ruberl, Austrian-American swimmer (born 1880)
- Tallulah Bankhead, American actress (born 1902)
- Doris Blackburn, Australian politician (born 1889)
- George Terwilliger, American director and screenwriter (born 1882)
- Yechezkel Kutscher, Israeli philologist and linguist (born 1909)
- David Sarnoff, Belarusian-American businessman (born 1891)
- Richard Baggallay, English colonel and cricketer (born 1884)
- Jack Cassidy, American actor and singer (born 1927)
- Vinko Aganec, Croatian lawyer and musicologist (born 1890)
- Clementine Churchill, English wife of Winston Churchill, Spouse of the Prime Minister of the United Kingdom (born 1885)
- Fay Compton, English actress (born 1894)
- Jean Lesage, Canadian lawyer and politician, 19th Premier of Quebec (born 1912)
- Amza Pellea, Romanian actor (born 1931)
- Anne Baxter, American actress (born 1923)
- Ian Stewart, Scottish keyboard player and manager (The Rolling Stones) (born 1938)
- Paul Verner, German politician (born 1911)
- Enrique Jorrín, Cuban violinist and composer (born 1926)
- Concha Piquer, Spanish singer and actress (born 1908)
- Suzanne Lilar, Belgian author and playwright (born 1901)
- József Antall, Hungarian historian and politician, 35th Prime Minister of Hungary (born 1932)
- Stuart Roosa, American colonel, pilot, and astronaut (born 1933)
- Donna J. Stone, American poet and philanthropist (born 1933)
- Vance Packard, American journalist, author, and critic (born 1914)
- Evgenii Landis, Ukrainian-Russian mathematician and academic (born 1921)
- Lawton Chiles, American soldier, lawyer, and politician, 41st Governor of Florida (born 1930)
- Marco Denevi, Argentinian author and screenwriter (born 1922)
- Mo Udall, American captain and politician (born 1922)
- Paul Cadmus, American painter and illustrator (born 1904)
- Joseph Heller, American novelist, short story writer, and playwright(born 1923)
- George Montgomery, American actor, stuntman, director, producer, and screenwriter (born 1916)
- Ndabaningi Sithole, Zimbabwean militant leader, founded Zimbabwe African National Union (born 1920)
- Ardito Desio, Italian geologist and explorer (born 1897)
- Jean Richard, French actor and singer (born 1921)
- Dee Brown, American historian and author (born 1908)
- Jay Wesley Neill, American murderer (born 1965)
- Keiko, Icelandic-Norwegian whale (born 1976)
- Heydar Aliyev, Azerbaijani general and politician, 3rd President of Azerbaijan (born 1923)
- Gangodawila Soma Thero, Sri Lankan monk and educator (born 1948)
- Robert Newmyer, American actor and producer (born 1956)
- Ramanand Sagar, Indian director, producer, and screenwriter (born 1917)
- Annette Stroyberg, Danish actress (born 1936)
- Gebran Tueni, Lebanese journalist and politician (born 1957)
- Paul Arizin, American basketball player (born 1928)
- Peter Boyle, American actor (born 1935)
- Kenny Davern, American clarinet player and saxophonist (born 1935)
- Raymond P. Shafer, American lawyer and politician, 38th Governor of Pennsylvania (born 1917)
- Alan Shugart, American engineer and businessman, co-founded Seagate Technology (born 1930)
- François al-Hajj, Lebanese general (born 1953)
- Ike Turner, American singer-songwriter, guitarist, and producer (born 1931)
- Avery Dulles, American cardinal and theologian (born 1918)
- Van Johnson, American actor, singer, and dancer (born 1916)
- Tassos Papadopoulos, Cypriot lawyer and politician, 5th President of Cyprus (born 1934)
- Tom Walkinshaw, Scottish race car driver, founded Tom Walkinshaw Racing (born 1946)
- Joe Allbritton, American banker, publisher, and philanthropist, founded the Allbritton Communications Company (born 1924)
- Nityanand Swami, Indian lawyer and politician, 1st Chief Minister of Uttarakhand (born 1927)
- David Tait, English rugby player (born 1987)
- Tom Laughlin, American actor, director, producer, and screenwriter (born 1931)
- Abdul Quader Molla, Bangladeshi journalist and politician (born 1948)
- Leo Sachs, German-Israeli biologist and academic (born 1924)
- Jang Sung-taek, North Korean general and politician (born 1946)
- Audrey Totter, American actress (born 1917)
- Norman Bridwell, American author and illustrator, created Clifford the Big Red Dog (born 1928)
- Ivor Grattan-Guinness, English mathematician, historian, and academic (born 1941)
- Herb Plews, American baseball player (born 1928)
- Yury Shutov, Russian politician (born 1946)
- Luis Bermejo, Spanish illustrator (born 1931)
- Frans Geurtsen, Dutch footballer (born 1942)
- Sharad Anantrao Joshi, Indian farmer and politician (born 1935)
- Evelyn S. Lieberman, American politician, White House Deputy Chief of Staff (born 1944)