Today in History : April 1

• 286 – Emperor Diocletian elevates his general Maximian to co-emperor with the rank of Augustus and gives him control over the Western regions of theRoman Empire.
• 325 – Crown Prince Jin Chengdi, age 4, succeeds his father Jin Mingdi as emperor of the Eastern Jin Dynasty.
• 457 – Majorian is acclaimed emperor by the Roman army.
• 527 – Byzantine Emperor Justin I names his nephew Justinian I as co-ruler and successor to the throne.
• 528 – The daughter of Emperor Xiaoming of Northern Wei was made the "Emperor" as a male heir of the late emperor by Empress Dowager Hu, deposed and replaced by Yuan Zhao the next day; she was the first female monarch in the History of China, but not widely recognised.
• 1293 – Robert Winchelsey leaves England for Rome, to be consecrated as Archbishop of Canterbury.
• 1318 – Berwick-upon-Tweed is captured by the Scottish from England.
• 1340 – Niels Ebbesen kills Gerhard III of Holstein in his bedroom, ending the 1332-1340 interregnum in Denmark.
• 1545 – Potosí is founded after the discovery of major silver deposits in the area.
• 1572 – In the Eighty Years' War, the Watergeuzen capture Brielle from the Spaniards, gaining the first foothold on land for what would become theDutch Republic.
• 1625 – A combined Spanish and Portuguese fleet of 52 ships commences the recapture of Bahia from the Dutch during the Dutch–Portuguese War.
• 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.
• 1833 – The Convention of 1833, a political gathering of settlers in Mexican Texas to help draft a series of petitions to the Mexican government, begins in San Felipe de Austin
• 1854 – Charles Dickens' novel Hard Times begins serialisation in his magazine, Household Words.
• 1865 – American Civil War: Battle of Five Forks.
• 1867 – Singapore becomes a British crown colony.
• 1871 – The first stage of the Brill Tramway opens.
• 1873 – The British steamer RMS Atlantic sinks off Nova Scotia, killing 547.
• 1887 – Mumbai Fire Brigade is established.
• 1891 – The Wrigley Company is founded in Chicago, Illinois.
• 1893 – The rank of Chief Petty Officer in the United States Navy is established.
• 1908 – The Territorial Force (renamed Territorial Army in 1920) is formed as a volunteer reserve component of the British Army.
• 1918 – The Royal Air Force is created by the merger of the Royal Flying Corps and the Royal Naval Air Service.
• 1919 – The Staatliches Bauhaus school is founded by Walter Gropius in Weimar.
• 1922 – Six Irish Catholic civilians are shot and beaten to death by a gang of policemen in Belfast, Northern Ireland.
• 1924 – Adolf Hitler is sentenced to five years in jail for his participation in the "Beer Hall Putsch". However, he spends only nine months in jail, during which he writes Mein Kampf.
• 1924 – The Royal Canadian Air Force is formed.
• 1933 – The recently elected Nazis under Julius Streicher organize a one-day boycott of all Jewish-owned businesses in Germany, ushering in a series of anti-Semitic acts.
• 1933 – English cricketer Wally Hammond sets a record for the highest individual Test innings of 336 not out, during a Test match against New Zealand.
• 1935 – India's central banking institution, The Reserve Bank of India is formed.
• 1936 – Odisha formerly known as Kalinga or Utkal becomes a state in India.
• 1937 – Aden becomes a British crown colony.
• 1937 – Spanish Civil War: Jaén, Spain is bombed by Nazi forces.
• 1939 – Spanish Civil War: Generalísimo Francisco Franco of the Spanish State announces the end of the Spanish Civil War, when the last of the Republican forces surrender.
• 1941 – Fantana Alba massacre: between 200 and 2,000 Romanian civilians are killed by Soviet Border Guards.
• 1941 – The Blockade Runner Badge for the German navy is instituted.
• 1941 – A military coup in Iraq overthrows the regime of 'Abd al-Ilah and installs Rashid Ali as Prime Minister.
• 1944 – Navigation errors lead to an accidental American bombing of the Swiss city of Schaffhausen.
• 1945 – World War II: Operation Iceberg – United States troops land on Okinawa in the last major campaign of the war.
• 1946 – Aleutian Island earthquake: A 8.6 magnitude earthquake near the Aleutian Islands creates a tsunami that strikes the Hawaiian Islands killing 159, mostly in Hilo.
• 1946 – Formation of the Malayan Union.
• 1947 – Paul becomes king of Greece, on the death of his childless elder brother, George II.
• 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.
• 1948 – Faroe Islands gain autonomy from Denmark.
• 1949 – Chinese Civil War: The Chinese Communist Party holds unsuccessful peace talks with the Nationalist Party in Beijing, after three years of fighting.
• 1949 – The Government of Canada repeals Japanese Canadian internment after seven years.
• 1949 – The 26 counties of the Irish Free State become Ireland.
• 1954 – President Dwight D. Eisenhower authorizes the creation of the United States Air Force Academy in Colorado.
• 1955 – The EOKA rebellion against the British Empire begins in Cyprus, with the goal of obtaining the desired unification ("enosis") with Greece.
• 1957 – The BBC broadcasts the spaghetti tree hoax on its current affairs programme Panorama.
• 1959 – Iakovos is enthroned as Greek Orthodox Archbishop of America.
• 1960 – The TIROS-1 satellite transmits the first television picture from space.
• 1967 – The United States Department of Transportation begins operation.
• 1969 – The Hawker Siddeley Harrier enters service with the Royal Air Force.
• 1970 – President Richard Nixon signs the Public Health Cigarette Smoking Act into law, requiring the Surgeon General's warnings on tobacco products and banning cigaretteadvertisements on television and radio in the United States, starting on January 1, 1971.
• 1971 – Bangladesh Liberation War: The Pakistan Army massacre over 1,000 people in Keraniganj Upazila, Bangladesh.
• 1973 – Project Tiger, a tiger conservation project, is launched in the Corbett National Park, India.
• 1974 – In the United Kingdom, the metropolitan and non-metropolitan counties come into being.
• 1976 – Apple Inc. is formed by Steve Jobs, Steve Wozniak, and Ronald Wayne.
• 1976 – Conrail takes over operations from six bankrupt railroads in the Northeastern U.S..
• 1976 – The Jovian–Plutonian gravitational effect, soon revealed as an April Fools' Day hoax, is first reported by British astronomer Patrick Moore.
• 1978 – The Philippine College of Commerce, through a presidential decree, becomes the Polytechnic University of the Philippines.
• 1979 – Iran becomes an Islamic republic by a 99% vote, officially overthrowing the Shah.
• 1986 – Sector Kanda: Communist Party of Nepal (Mashal) cadres attacks a number of police stations in Kathmandu, seeking to incite a popular rebellion.
• 1989 – Margaret Thatcher's new local government tax, the Community Charge (commonly known as the "poll tax"), is introduced in Scotland.
• 1992 – Start of the Bosnian War.
• 1997 – Comet Hale-Bopp is seen passing over perihelion.
• 1999 – Nunavut is established as a Canadian territory carved out of the eastern part of the Northwest Territories.
• 2001 – An EP-3E United States Navy surveillance aircraft collides with a Chinese People's Liberation Army Shenyang J-8 fighter jet. The Navy crew makes an emergency landing in Hainan, People's Republic of China and is detained.
• 2001 – Former President of Federal Republic of Yugoslavia Slobodan Milošević surrenders to police special forces, to be tried on war crimes charges.
• 2001 – Same-sex marriage becomes legal in the Netherlands, the first country to allow it.
• 2006 – The Serious Organised Crime Agency, dubbed the "British FBI", is created in the United Kingdom.
• 2009 – Croatia and Albania join NATO.
• 2011 – After protests against the burning of the Quran turn violent, a mob attacks a United Nations compound in Mazar-i-Sharif, Afghanistan, resulting in the deaths of thirteen people, including eight foreign workers.