March 31 is the 90th day of the year (91st in leap years) in the Gregorian calendar. There are 275 days remaining until the end of the year.
It is the last day of the first quarter of the year.
Up to 1900
- 307 – After divorcing his wife Minervina, Constantine marries Fausta, the daughter of the retired Roman Emperor Maximian.
- 1492 – Queen Isabella of Castile issues the Alhambra Decree, ordering her 150,000 Jewish and Muslim subjects to convert to Christianity, or face being forced to leave.
- 1547 – King Henry II of France becomes king on his 28th birthday, following the death of his father, King Francis I of France.
- 1717 – A sermon on "The Nature of the Kingdom of Christ" by Benjamin Hoadly, the Bishop of Bangor, provoked the Bangorian Controversy.
- 1774 – American Revolutionary War: The United Kingdom of Great Britain orders the port of Boston, Massachusetts closed in the Boston Port Act.
- 1822 – Massacre of the population of the Greek island of Chios by Ottoman Empire soldiers following an attempted rebellion.
- 1829 – Francesco Saverio Castiglione is elected Pope, becoming Pope Pius VIII.
- 1854 – Commodore Matthew Perry signs the Treaty of Kanagawa with the Japanese government, opening the ports of Shimoda and Hakodate to American trade.
- 1866 – Spanish Navy bombs the harbour of Valparaíso, Chile
- 1885 – The United Kingdom establishes a protectorate over Bechuanaland, present-day Botswana.
- 1889 – The Eiffel Tower is inaugurated.
- 1899 – Malolos, capital of the First Philippine Republic, is captured by American forces.
1901 – 2000
- 1901 – The 1901 Black Sea earthquake occurs.
- 1903 – Richard Pearse reportedly flies a heavier-than-air machine in powered flight near Pleasant Point, South Canterbury, New Zealand; some claim 1902.
- 1906 – The Intercollegiate Athletic Association of the United States (later National Collegiate Athletic Association) is established to set rules for amateur sports in the United States.
- 1909 – Serbia accepts Austrian control over Bosnia-Herzegovina.
- 1909 – Building work on the RMS Titanic begins.
- 1910 – Six North Staffordshire pottery towns merge to form Stoke-on-Trent.
- 1917 – The United States takes possession of the United States Virgin Islands after paying $25 million to Denmark.
- 1918 – Daylight Saving Time goes into effect in the United States for the first time.
- 1918 – Massacre of ethnic Azerbaijanis is committed by groups of the Armenian Revolutionary Federation and Bolsheviks. Almost 12,000 Azerbaijani Muslims are killed.
- 1921 – The Royal Australian Air Force is formed.
- 1930 – The Motion Pictures Production Code is instituted, imposing strict guidelines on the treatment of sex, crime, religion and violence in movies for the next forty years.
- 1931 – An earthquake destroys Managua, Nicaragua, killing 2,000.
- 1931 – TWA Flight 599 crashes near Bazaar, Kansas, killing 8 people, including University of Notre Dame American football coach Knute Rockne.
- 1933 – The Civilian Conservation Corps is established with the mission to relieve unemployment.
- 1942 – World War II: Japanese forces invade Christmas Island.
- 1945 – World War II: A defecting German pilot delivers a Messerschmitt Me 26ZA-1, the world's first jet-powered fighter aircraft, to the Americans.
- 1949 – Newfoundland and Labrador joins the Canadian Confederation and becomes the 10th province of Canada.
- 1958 – Canadian Federal Election: The Progressive Conservatives under John Diefenbaker win 208 out of 265 seats in parliament, setting a Canadian record for the number of seats occupied by a single party.
- 1959 – The 14th Dalai Lama, Tenzin Gyatso, crosses the border into India and is granted political asylum.
- 1964 – The Dictatorship in Brazil, under general Castello Branco, begins.
- 1965 – Iberia Airlines Convair 440 flight crashes into the sea off Tangier, Morocco, killing 47 out of the 51 people on board.
- 1966 – The Soviet Union launches Luna 10 which later becomes the first spaceprobe to enter orbit around the Moon.
- 1966 – In the United Kingdom the Labour Party under Harold Wilson is elected to a second consecutive term in government.
- 1967 – Jimi Hendrix burns his guitar for the first time at London's Astoria Theatre. He is sent to the hospital afterwards for burns on his hands.
- 1968 – United States President Lyndon B. Johnson announces he will not run for re-election.
- 1970 – Explorer 1 re-enters the Earth's atmosphere (after 12 years in orbit).
- 1970 – Eight terrorists from the Japanese Red Army hijacked a Japan Airlines Boeing 727 at Tokyo International Airport, using samurai swords and carrying a bomb.
- 1979 – In Jerusalem, Israel, Gali Atari & Milk and Honey win the twenty-fourth Eurovision Song Contest for Israel singing "Hallelujah".
- 1979 – The last British soldier leaves the Maltese Islands. Malta is no longer a military base.
- 1985 – The first ever WrestleMania is held in New York City's Madison Square Garden.
- 1986 – A Mexicana Boeing 727 en route to Puerto Vallarta catches fire and crashes in the mountains northwest of Mexico City, killing 166.
- 1986 – Six metropolitan county councils are abolished in England.
- 1990 – Boxer Julio César Chávez defeats Meldrick Taylor to unify the boxing's world junior welterweight title in a very controversial fight known as "Thunder Meets Lightning".
- 1991 – The Warsaw Pact comes to an end.
- 1992 – The television news program Dateline NBC premieres.
- 1993 – Actor Brandon Lee is accidentally killed during the filming of The Crow.
- 1994 – The journal Nature reports the finding in Ethiopia of the first complete Australopithecus afarensis skull (see Human evolution).
- 1995 – TAROM Flight 371 crashes in Balotesti, Romania, killing all 60 people on board.
- 1995 – Popular Tex-Mex singer Selena Quintanilla is murdered by her assistant Yolanda Saldivar in a Corpus Christi, Texas motel after a heated discussion where the latter was accused of ripping off the artist's fan club.
- 1997 – At age 16, Martina Hingis becomes the youngest female tennis players to reach Number 1 in the world rankings.
- 1998 – Netscape gives the code base of its browser under an open source license agreement, thus creating Mozilla Foundation, a not-for-profit corporation to oversee the development of Mozilla.
From 2001
- 2002 – Major flooding affects the city of Santa Cruz de Tenerife in the Canary Islands.
- 2004 – Google announces Gmail, the first web-based mail service to offer 1 gigabyte of storage.
- 2004 – In Fallujah, Iraq, 4 American contractors working for Blackwater USA, are killed and their bodies mutilated after being ambushed.
- 2004 – Sandton Square in Johannesburg, South Africa, is renamed Nelson Mandela Square.
- 2013 – The UK records it coldest Easter Sunday. Overall, it was the coldest March there since 1962.
- 2014 – South Korea and North Korea exchange fire over their western maritime border.
- 2014 – The United Nations International Court of Justice rules that Japan's Antarctic whaling program is not scientific but commercial.
- 2014 – Manuel Valls replaces Jean-Marc Ayrault as Prime Minister of France.
- 2016 – A flyover collapses in Kolkata, India, killing at least 20 people.
- 2017 – Former South Korean President Park Geun-hye is arrested on corruption charges.
- 2019 – Comedian Volodymyr Zelensky wins the first round of Ukraine's Presidential election, ahead of Petro Poroshenko.
Up to 1800
- 250 – Constantius Chlorus, Roman Emperor (d. 306)
- 1360 – Philippa of Lancaster, Queen of Portugal (d. 1415)
- 1425 – Bianca Maria Visconti, Duchess of Milan (d. 1468)
- 1499 – Pope Pius IV (d. 1565)
- 1504 – Guru Angad Dev, 2nd Sikh Guru (d. 1552)
- 1519 – King Henry II of France (d. 1559)
- 1536 – Ashikaga Yoshikatsu, Japanese shogun (d. 1565)
- 1576 – Louise Juliana of Nassau, Regent of Bohemia (d. 1644)
- 1596 – René Descartes, French mathematician (d. 1650)
- 1621 – Andrew Marvell, English poet (d. 1678)
- 1635 – Patrick Gordon, Scottish general in the Russian army (d. 1699)
- 1644 – Henry Winstanley, English painter and engineer (d. 1703)
- 1651 – Karl II, Elector Palatine (d. 1685)
- 1675 – Pope Benedict XIV (d. 1758)
- 1684 – Francesco Durante, Italian composer (d. 1755)
- 1685 – Johann Sebastian Bach, German composer (d. 1750)
- 1718 – Mariana Victoria of Spain (d. 1781)
- 1723 – King Frederick V of Denmark (d. 1766)
- 1732 – Joseph Haydn, Austrian composer (d. 1809)
- 1747 – Johann Abraham Peter Schulz, German musician and composer (d. 1800)
- 1777 – Charles Cagniard de la Tour, French physicist (d. 1859)
- 1788 – Jessadabodindra (Rama III), King of Siam (d. 1851)
- 1794 – Thomas McKean Thompson McKennan, American politician (d. 1852)
1801 – 1900
- 1808 – James Pinckney Henderson, 1st Governor of Texas (d. 1858)
- 1809 – Edward FitzGerald, English poet (d. 1883)
- 1809 – Nikolai Gogol, Russian writer (d. 1852)
- 1819 – Chlodwig, Prince of Hohenlohe-Schillingsfürst, German statesman (d. 1901)
- 1822 – Dmitry Grigorovich, Russian writer (d. 1900)
- 1831 – Archibald Scott Couper, Scottish chemist (d. 1892)
- 1847 – Yegor Ivanovich Zolotarev, Russian mathematician (d. 1878)
- 1848 – Diederik Korteweg, Dutch mathematician (d. 1941)
- 1848 – William Waldorf Astor, 1st Viscount Astor, American-born British financier, writer and statesman (d. 1919)
- 1851 – Francis Bell, 20th Prime Minister of New Zealand (d. 1936)
- 1853 – Isaac Bayley Balfour, Scottish botanist (d. 1922)
- 1870 – James M. Cox, Governor of Ohio (d. 1957)
- 1871 – Arthur Griffith, Irish politician (d. 1922)
- 1872 – Sergei Diaghilev, Russian ballet impresario, publicist, curator and art critic (d. 1929)
- 1872 – Alexandra Kollontai, Russian Communist revolutionary (d. 1952)
- 1873 – William D. Denney, Governor of Delaware (d. 1953)
- 1876 – Borisav Stankovic, Serbian writer (d. 1927)
- 1878 – Jack Johnson, American boxer (d. 1946)
- 1884 – Adriaan van Maanen, Dutch-American astronomer (d. 1946)
- 1884 – Henri Queuille, Prime Minister of France (d. 1970)
- 1890 – William Lawrence Bragg, Australian-British physicist (d. 1971)
- 1890 – Ben Adams, American athlete (d. 1961)
- 1893 – Clemens Krauss, Austrian conductor (d. 1954)
- 1900 – Prince Henry, Duke of Gloucester (d. 1974)
1901 – 1950
- 1904 – Sam Zimbalist, American film producer (d. 1958)
- 1905 – Robert Stevenson, British director, screenwriter and producer (d. 1986)
- 1906 – Shin'ichiro Tomonaga, Japanese physicist (d. 1979)
- 1913 – Etta Baker, American blues musician and singer (d. 2006)
- 1914 – Octavio Paz, Mexican writer (d. 1998)
- 1914 – Dagmar Lange (Maria Lang), Swedish writer (d. 1991)
- 1915 – Shoichi Yokoi, Japanese sergeant (d. 1997)
- 1916 – Lucille Bliss, American actress (d. 2012)
- 1917 – Dorothy DeLay, American violin instructor (d. 2002)
- 1920 – Deborah Cavendish, Duchess of Devonshire, English aristocrat (d. 2014)
- 1922 – Richard Kiley, American actor (d. 1999)
- 1922 – William Stanley Peart, British physician and clinical researcher (d. 2019)
- 1925 – Andrea Bianchi, Italian movie director and writer
- 1926 – John Fowles, English novelist (d. 2005)
- 1927 – César Chávez, American labor activist (d. 1993)
- 1927 – Vladimir Ilyushin, Russian pilot (d. 2010)
- 1927 – Eduardo Martinez Somalo, Spanish cardinal
- 1928 – Gordie Howe, Canadian ice hockey player (d. 2016)
- 1929 – Liz Claiborne, Belgian-born fashion designer (d. 2007)
- 1930 – Yehuda Nir, Polish-born psychiatrist (d. 2014)
- 1930 – Jim Mutscheller, American football player (d. 2015)
- 1932 – Nagisa Oshima, Japanese movie director and screenwriter (d. 2013)
- 1934 – Richard Chamberlain, American actor
- 1934 – Shirley Jones, American singer and actress
- 1934 – Carlo Rubbia, Italian physicist
- 1935 – Herb Alpert, American trumpeter and bandleader
- 1937 – Sid Ahmed Ghozali, former Prime Minister of Algeria
- 1938 – David Steel, Scottish politician
- 1938 – Sheila Dikshit, Indian politician
- 1939 – Zviad Gamsakhurdia, President of the Republic of Georgia (d. 1993)
- 1939 – Volker Schlöndorff, German movie director
- 1939 – Karl-Heinz Schnellinger, German footballer
- 1940 – Barney Frank, American politician
- 1940 – Patrick Leahy, American politician
- 1943 – Christopher Walken, American actor
- 1943 – Sharon Hampson, Canadian singer and musician (Sharon, Lois & Bram)
- 1944 – Mick Ralphs, English guitarist
- 1944 – Angus King, 72nd Governor of Maine
- 1945 – Myfanwy Talog, Welsh actress (d. 1995)
- 1945 – Valerie Curtin, American actress and screenwriter
- 1946 – F'Murr, French comic artist (d. 2018)
- 1947 – Kristian Blak, Danish musician and recording executive
- 1947 – Eliyahu M. Goldratt, Israeli physicist (d. 2011)
- 1947 – César Gaviria, 36th President of Colombia
- 1948 – Al Gore, 45th Vice President of the United States
- 1948 – David Eisenhower, American author and educator
- 1948 – Natalia Dubova, Russian ice dancer and coach
- 1948 – Rhea Perlman, American actress
- 1948 – Gary Doer, Canadian politician, 20th Premier of Manitoba
1951 – 1975
- 1952 – Dermot Morgan, Irish comedian and actor (d. 1998)
- 1953 – Dennis Kamakahi, American musician (d. 2014)
- 1954 – Laima Vaikule, Latvian actress, singer, director and choreographer
- 1955 – Angus Young, Scottish-Australian musician (AC/DC)
- 1955 – Svetozar Marovic, only President of Serbia and Montenegro
- 1957 – Alan Duncan, British politician
- 1958 – Tony Cox, American actor
- 1960 – Popa Chubby, American blues singer and guitarist
- 1964 – Christian Allard, French-born Scottish politician
- 1964 – Oleksandr Turchynov, former interim President of Ukraine
- 1965 – Tom Barrasso, American ice hockey player
- 1965 – Jean-Christophe Lafaille, French mountaineer (d. 2006)
- 1966 – Roger Black, British athlete
- 1969 – Francesco Moriero, Italian footballer
- 1970 – Alenka Bratusek, 7th Prime Minister of Slovenia
- 1971 – Ewan McGregor, Scottish actor
- 1971 – Pavel Bure, Russian ice hockey player
- 1971 – Martin Atkinson, English footballer and referee
- 1971 – Craig McCracken, American animator, producer and screenwriter
- 1972 – Alejandro Amenabar, Chilean-Spanish movie director, screenwriter and composer
- 1972 – Evan Williams, American businessman
- 1975 – Adam Green, American director, producer and screenwriter
From 1976
- 1978 – Daniel Mays, English actor
- 1978 – Alexander Douglas-Hamilton, 16th Duke of Hamilton, Scottish nobleman
- 1979 – Danny Invincibile, Australian footballer
- 1979 – Euan Burton, Scottish judoka
- 1979 – Josh Kinney, American baseball player
- 1980 – Maaya Sakamoto, Japanese voice actress and singer
- 1980 – Michael Ryder, American ice hockey player
- 1980 – Pa Dembo Touray, Gambian footballer
- 1982 – Tal Ben Haim, Israeli footballer
- 1983 – Hashim Amla, South African cricketer
- 1983 – Silver Leppik, Estonian basketball player
- 1984 – Alberto Junior Rodríguez, Peruvian footballer
- 1984 – Eddie Johnson, American soccer player
- 1986 – Andreas Dober, Austrian footballer
- 1987 – Nordin Amrabat, Dutch-Moroccan footballer
- 1987 – Georg Listing, German musician (Tokio Hotel)
- 1987 – Humpy Koneru, Indian chess player
- 1989 – Pablo Piatti, Argentine footballer
- 1989 – Liu Zige, Chinese swimmer
- 1990 – Bang Yong-guk, South Korean rapper, actor and dancer
- 1990 – Lyra McKee, Northern Irish journalist (d. 2019)
- 1994 – Thomas Batuello, American musician and actor
- 1998 – Anna Seidel, German speed skater
Up to 1900
- 1074 – Yorimichi Fujiwara, Regent of Japan (b. 992)
- 1204 – Eleanor of Aquitaine, Queen of France and England (b. 1121)
- 1340 – Ivan I of Russia (b. 1288)
- 1547 – Francis I of France (b. 1494)
- 1567 – Philip I of Hesse (b. 1504)
- 1621 – Philip III of Spain (b. 1578)
- 1671 – Anne Hyde, Duchess of York (b. 1637)
- 1703 – Johann Christoph Bach, German composer (b. 1642)
- 1727 – Sir Isaac Newton, English mathematician and physicist (b. 1643)
- 1741 – Pieter Burmann the Elder, Dutch classical scholar (b. 1668)
- 1797 – Olaudah Equiano, Nigerian-American slave and activist (b. around 1745)
- 1837 – John Constable, English painter (b. 1776)
- 1850 – John C. Calhoun, 7th Vice President of the United States (b. 1782)
- 1855 – Charlotte Brontë, English writer (b. 1816)
- 1877 – Antoine Auguste Cournot, French mathematician (b. 1801)
- 1885 – Franz Wilhelm Abt, German composer (b. 1819)
1901 – 2000
- 1913 – J. P. Morgan, American financier (b. 1837)
- 1915 – Wyndham Halswelle, British runner (b. 1882)
- 1917 – Emil von Behring, German doctor, won the Nobel Prize in Physiology or Medicine (1901) (b. 1854)
- 1920 – Lothar von Trotha, German general (b. 1848)
- 1929 – Myron T. Herrick, American politician, Governor of Ohio (b. 1854)
- 1931 – Knute Rockne, American football coach (b. 1888)
- 1944 – Mineichi Koga, Japanese general (b. 1885)
- 1945 – Anne Frank, German-born diarist (b. 1929)
- 1945 – Hans Fischer, German chemist (b. 1881)
- 1946 – Martin Davey, Governor of Ohio (b. 1884)
- 1949 – Friedrich Bergius, German chemist (b. 1856)
- 1956 – Ralph DePalma, Italian racing driver (b. 1884)
- 1968 – Gary Lowdermilk, American baseball player (b. 1885)
- 1972 – Meena Kumari, Indian actress (b. 1932)
- 1972 – Ramon Iglesias i Navarri, Catalan bishop of Urgell, co-Prince of Andorra (b. 1889)
- 1975 – Percy Alliss, English golfer (b. 1897)
- 1976 – Paul Strand, American photographer and movie maker (b. 1890)
- 1978 – Charles Herbert Best, American-Canadian medical scientist (b. 1899)
- 1980 – Jesse Owens, American athlete (b. 1913)
- 1986 – O'Kelly Isley, Jr., American singer (The Isley Brothers) (b. 1937)
- 1986 – Jerry Paris, American actor and director (b. 1925)
- 1988 – William McMahon, 20th Prime Minister of Australia (b. 1908)
- 1993 – Brandon Lee, American actor (b. 1965)
- 1995 – Selena, Mexican-American singer-songwriter (b. 1971)
- 1997 – Friedrich Hund, German physicist (b. 1896)
- 1998 – Bella Abzug, American politician (b. 1920)
From 2001
- 2001 – Clifford Shull, American physicist (b. 1915)
- 2005 – Terri Schiavo, American patient in right-to-die case (b. 1963)
- 2007 – Paul Watzlawick, American psychologist (b. 1921)
- 2008 – Jules Dassin, American movie director (b. 1911)
- 2009 – Jarl Alfredius, Swedish television journalist (b. 1943)
- 2009 – Raul Alfonsin, President of Argentina (b. 1927)
- 2012 – Dale R. Corson, American physicist (b. 1914)
- 2013 – Charles Amarin Brand, French archbishop (b. 1920)
- 2014 – Irene Fernandez, Malaysian activist (b. 1946)
- 2014 – Frankie Knuckles, American DJ and record producer (b. 1955)
- 2014 – Gonzalo Anes, Spanish economist, professor and historian (b. 1931)
- 2014 – Charles Keating, American banker (b. 1923)
- 2014 – David Hannay, Australian movie producer (b. 1939)
- 2014 – Ferdinand Masset, Swiss politician (b. 1920)
- 2014 – Roger Somville, Belgian painter (b. 1923)
- 2016 – Georges Cottier, Swiss cardinal (b. 1922)
- 2016 – Ronnie Corbett, Scottish actor and comedian (b. 1930)
- 2016 – Imre Kertész, Hungarian writer (b. 1929)
- 2016 – Zaha Hadid, Iraqi-British architect (b. 1950)
- 2016 – Douglas Wilmer, English actor (b. 1920)
- 2016 – Hans-Dietrich Genscher, German politician and diplomat (b. 1927)
- 2016 – Denise Robertson, English broadcaster (b. 1932)
- 2017 – Halit Akçatepe, Turkish actor (b. 1938)
- 2017 – Gilbert Baker, American LGBT activist, creator of the Rainbow flag (b. 1951)
- 2017 – William Thaddeus Coleman, Jr., American lawyer, judge and politician (b. 1920)
- 2017 – Mike Hall, British endurance cyclist (b. 1981)
- 2017 – James Rosenquist, American artist (b. 1933)
- 2017 – Radley Metzger, American pornographic filmmaker (b. 1929)
- 2017 – Richard Nelson Bolles, American writer (b. 1927)
- 2017 – Jerrier A. Haddad, American computer engineer (b. 1922)
- 2017 – Amy Ridenour, American political activist (b. 1959)
- 2018 – Margarita Carrera, Guatemalan philosopher (b. 1929)
- 2018 – Luigi De Filippo, Italian actor (b. 1930)
- 2018 – Peg Lautenschlager, American attorney and politician (b. 1955)
- 2018 – Michael Tree, American violist (b. 1934)
- 2019 – Peter Coleman, Australian writer and politician (b. 1928)
- 2019 – Hedi Turki, Tunisian painter (b. 1922)
- 2019 – Nipsey Hussle, American rapper (b. 1985)
- 2020 – Vincent Marzello, American voice actor (b. 1951)