April 1

• April 1, 1778
  Oliver Pollock, a New Orleans businessman, creates "$" symbol
• April 1, 1826
  Samuel Morey, an American inventor, patents the internal combustion engine, an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber
• April 1, 1851
  Rama IV, also known as King Mongkut, succeeds the throne of King of Siam and begins to embrace Western innovations and initiates the modernization of Siam
• April 1, 1865
  At the Battle of Five Forks in Petersburg, Virginia, General Robert E. Lee begins his final offensive
• April 1, 1867
  The British government establishes the Straits Settlements, consisted of Singapore, Penang, and Malacca, as a separate Crown Colony
• April 1, 1873
  The British White Star steamship Atlantic, enroute to New York City from Liverpool with 811 passengers under Captain James Agnew Williams, sinks off Nova Scotia killing 565 people, mostly women and children
• April 1, 1933
  Germany begins persecution of Jews, boycotting Jewish businesses
• April 1, 1939
  After three years of Spanish Civil War general Francisco Franco proclaims victory in a radio speech, thus becomes dictator of Spain
• April 1, 1957
  Trial begins in Budapest, Hungary against participants' Hungarian Uprising
• April 1, 1966
  China's Cultural Revolution begins in order to impose Maoism as the dominant ideology and to enforce communism in the country by removing capitalist and cultural elements from Chinese society
• April 1, 1975
  Cambodia President Lon Nol flees for Red Khmer
• April 1, 1976
  American entrepreneur Steven Jobs and electronics engineer Stephen Wozniak incorporate the Apple Computer Company in California, United States, to sell hand-built personal computer called Apple I
• April 1, 1979
  Iran officially becomes an Islamic Republic by a 98 percent vote, overthrowing the Shah Mohammad Reza Pahlavi and forcing him into exile
• April 1, 2001
  The Act on the Opening up of Marriage, which allows same-sex couples to legally marry for the first time in the world, goes into effect in the Netherlands