April 1 is the 91th day of the year (92nd in leap years) in the Gregorian calendar, with 274 days remaining.
- 527 - Byzantine Emperor Justin I names his nephew Justinian I as co-ruler and successor to the throne.
- 1789 - In New York City, the United States House of Representatives holds its first quorum and elects Frederick Muhlenberg of Pennsylvania as its first House Speaker.
- 1826 - Samuel Morey patents the internal combustion engine.
- 1865 - American Civil War: Battle of Five Forks - In Petersburg, Virginia, Confederate General Robert E. Lee begins his final offensive.
- 1867 - Singapore becomes British crown colony.
- 1873 - The British steamer SS Atlantic[?] sinks off Nova Scotia killing 547.
- 1918 - The Royal Flying Corps is replaced by the Royal Air Force.
- 1924 - Adolf Hitler is sentenced to five years in jail for his participation in the "Beer Hall Putsch." However he was only in jail for nine months.
- 1933 - The recently elected Nazis under Julius Streicher organize a one-day boycott of all Jewish-owned businesses in Germany, ushering in the series of anti-Semitic acts that will be known as the Holocaust.
- 1934 - Bonnie and Clyde kill two young highway patrolmen near Grapevine, Texas.
- 1937 - Aden becomes a British crown colony.
- 1945 - World War II: United States troops land on Okinawa in the last campaign of the war.
- 1946 - A 7.8 magnitude earthquake near the Aleutian Islands creates a tsunami that strikes the Hawaiian Islands killing 159 (mostly in Hilo, Hawaii).
- 1948 - Cold War: Berlin Airlift - Military forces, under direction of the Soviet-controlled government in East Germany, set-up a land blockade of West Berlin.
- 1949 - Newfoundland joins Canada
- 1949 - Communist Party of China held peace talks with the Kuomintang in Beijing, after three years of civil war. However, more than six thousand pro-communist students were protesting in Nanjing and some were killed. The talk was not successful.
- 1954 - President Dwight D. Eisenhower authorizes the creation of the United States Air Force Academy in Colorado.
- 1960 - The United States launches the first weather satellite[?], TIROS-1.
- 1967 - The United States Department of Transportation begins operation.
- 1969 - The Hawker Siddeley Harrier enters service with the RAF.
- 1970 - President Richard Nixon signs the Public Health Cigarette Smoking Act[?] into law banning cigarette advertisements in the United States starting on January 1, 1971.
- 1973 - Project Tiger, a tiger conservation project, is launched in the Corbett National Park[?], India.
- 1976 - Apple Computer Company is formed by Steve Jobs and Steve Wozniak.
- 1979 - Ruhollah Khomeini proclaims Iran to be an Islamic Republic.
- 1999 - Nunavut is established as a Canadian territory carved from the eastern part of the Northwest Territories.
- 2001 - An EP-3E United States Navy plane collides with a Chinese fighter jet. The Navy crew makes an emergency landing in China and are detained. The American crew would later be released on April 11 and the Chinese fighter pilot was lost and presumed dead.
- 2001 - Former Yugoslav president Slobodan Milosevic surrenders to police special forces, to be tried on charges of war crimes.
- 1578 - William Harvey, physician, discovered blood circulation[?]
- 1776 - Sophie Germain, mathematician (+ 1831)
- 1875 - Edgar Wallace[?], writer (+ 1932)
- 1815 - Otto von Bismarck, politician (+ 1898)
- 1834 - James Fisk, entrepreneur (+ 1872)
- 1866 - Ferruccio Busoni, pianist and composer (+ 1924)
- 1873 - Sergei Rachmaninoff, composer, pianist, and conductor (+ 1943)
- 1883 - Lon Chaney[?], actor (+ 1930)
- 1885 - Wallace Beery, actor (+ 1949)
- 1895 - Alberta Hunter[?], singer (+ 1984)
- 1901 - Whittaker Chambers, spy (+ 1961)
- 1915 - Otto Wilhelm Fischer[?], actor
- 1920 - Toshirô Mifune, actor (+ 1997)
- 1922 - William Manchester[?], writer
- 1926 - Anne McCaffrey, science fiction author
- 1928 - Jane Powell, dancer, actress, singer
- 1929 - Milan Kundera, author
- 1931 - Rolf Hochhuth, writer
- 1932 - Debbie Reynolds, actress
- 1948 - Jimmy Cliff, musician
- 1949 - Gil Scott-Heron, musician, composer
- 1953 - Barry Sonnenfeld[?], producer, director
- 1955 - Ronnie Burk, surrealist and AIDS activist (+ 2003)
- 1971 - Method Man, musician
- 1204 - Eleanor of Aquitaine, wife of Henry II of England
- 1914 - Rube Waddell[?], Baseball Hall of Famer
- 1917 - Scott Joplin, musician, composer
- 1922 - Emperor Karl of Austria
- 1930 - Empress Zawditu of Ethiopia[?]
- 1946 - Noah Beery[?], actor
- 1947 - King George II of Greece
- 1950 - Charles R. Drew, physician
- 1968 - Lev Davidovich Landau, Russian physicist
- 1976 - Max Ernst, artist
- 1984 - Marvin Gaye, singer
- 1991 - Martha Graham[?], dancer, choreographer
- 2003 - Leslie Cheung, actor
- 2003 - Hyosuke Kujiraoka[?], a former vice speaker of the House of Representatives
March 31 -
April 2 -
March 1 -
May 1 - more
historical anniversaries
See Also: January, February, March, April, May, June, July, August, September, October, November, December