June 17

• June 17, 362
  Roman emperor Julian decrees religious toleration in the empire and attempts to reestablish paganism
• June 17, 1397
  The Union of Kalmar, which grows out of the dynastic ties of the Scandinavian countries, unites Denmark, Sweden and Norway under one monarch
• June 17, 1579
  Sir Francis Drake sails into San Francisco Bay and proclaims English sovereignty over New Albion in modern-day California
• June 17, 1696
  John III Sobieski, King of Lithuania and Poland, dies
• June 17, 1767
  English navigator Samuel Wallis becomes the first European to visit Tahiti in existing records
• June 17, 1789
  The Third Estate of the Estates-General in France declare itself a national assembly, and undertake to frame a constitution
• June 17, 1797
  Mohammad Khan Qajar, cruel ruler of Persia, is killed, and his nephew Fath Ali Shah succeeded him
• June 17, 1848
  Austrian General Alfred Windisch-Grätz crushes a Czech uprising in Prague against Habsburg control
• June 17, 1930
  United States President Herbert Hoover signs the Hawley-Smoot Tariff bill, which increases some 900 American import duties, so contributing to the depth of the Depression
• June 17, 1942
  First World War II American expeditionary force lands in Africa
• June 17, 1944
  Republic of Iceland proclaimed at Thingvallir, Iceland
• June 17, 1950
  Julius Rosenberg is arrested in the US on suspicion of espionage, accused of heading a spy ring that passed top-secret information concerning the atomic bomb to the Soviet Union
• June 17, 1967
  China becomes world's fourth thermonuclear power
• June 17, 1972
  Five men are arrested for breaking and entering into the DNC headquarters at the Watergate complex, beginning the Watergate scandal

May 1

• May 1, 305
  Constantius Chlorus and Galerius become Western and Eastern emperors, after Diocletian leaves the imperial office due to illness becoming the only Roman emperor to voluntarily abdicate the position
• May 1, 408
  Theodosius II succeeded to the throne of Constantinople
• May 1, 1486
  Christopher Columbus convinces Queen Isabella to fund expedition to the West Indies
• May 1, 1648
  The Ottomans begin the Siege of Candia in order to capture Crete from the Venetians
• May 1, 1707
  Act of Union merging the Scottish and the English Parliaments takes effect, thus establishing the Kingdom of Great Britain
• May 1, 1711
  Arch duke Charles VI of Austria and Hungarian rebellion sign Treaty of Szatmár
• May 1, 1759
  France surrenders Guadeloupe to Great Britain
• May 1, 1776
  Adam Weishaupt, a German philosopher, founds the secret society of Illuminati to oppose superstition, religious influence over public life, abuses of state power, and to support gender equality
• May 1, 1786
  Opera "Marriage of Figaro", composed by Wolfgang Amadeus Mozart, an Austrian influential composer of the Classical era, is premiered in Vienna
• May 1, 1840
  Britain issues the world's first postage stamp, "Penny Blacks", depicting a picture of Queen Victoria, as prepaid postage innovation
• May 1, 1851
  The Great Exhibition in London, the world's first international Expo, is opened in Crystal Palace, a cast-iron and plate-glass building erected in Hyde Park, as a showcase for industrial accomplishments of Great Britain and other countries
• May 1, 1853
  Argentina adopts its liberal and federal Constitution constitution
• May 1, 1857
  William Walker, conqueror of Nicaragua, surrenders to the US Navy under the pressure of the Central American armies
• May 1, 1862
  USA Army captain David Farragut recaptures New Orleans, Louisiana which stops cotton sales by the Confederacy a revenue shortage that led to printed money and hyperinflation
• May 1, 1869
  Folies Bergère, a cabaret music hall, opens in Paris
• May 1, 1873
  Emperor Franz Jozef opens 5th World's Fair in Vienna, Austria-Hungary
• May 1, 1876
  Queen of the United Kingdom Victoria takes title of Empress of India by Royal Titles Act
• May 1, 1877
  US President Rutherford B. Hayes orders the withdrawal all Federal troops from the South, ending Reconstruction
• May 1, 1884
  Construction begins on the first steel-skeleton skyscraper, a 10-story structure in Chicago, designed by William Le Baron Jenney and built by the Home Insurance Co. of New York
• May 1, 1889
  Bayer, a German chemical and pharmaceutical company, introduces aspirin in powder form
• May 1, 1896
  Naser al-Din Shah Qajar, shah of Persia, is murdered by Mirza Reza Kermani, a follower of Jamal al-Din al-Afghani, at age 65
• May 1, 1898
  The American Asiatic Squadron under George Dewey destroy the Spanish Pacific Squadro during the Battle of Manila Bay
• May 1, 1924
  Admiral Pavlos Kountouriotis becomes the first President of Greece
• May 1, 1925
  Cyprus is declared a British Crown Colony
• May 1, 1930
  The dwarf planet Pluto is officially named
• May 1, 1931
  Empire State Building is officially opened, when United States President Herbert Hoover turns on the building's lights with the push of a button from Washington, D.C
• May 1, 1932
  Paul Doumer, President of France, is assassinated by mentally unstable Russia's Paul Gargalov
• May 1, 1947
  The U.S. Central Intelligence Agency is created
• May 1, 1956
  A doctor in Japan reports an "epidemic of an unknown disease of the central nervous system," marking the official discovery of Minamata disease
• May 1, 1960
  Russia shoots down American pilot Francis Gary Powers' U-2 spy plane over Sverdlovsk
• May 1, 1964
  At Dartmouth College, in Hanover, New Hampshire, the BASIC programming language runs for the first time, developed by professors John Kemeny and Thomas Kurtz for a General Electric 225 mainframe computer
• May 1, 1978
  Japan's Naomi Uemura, traveling by dog sled, becomes the first person to reach the North Pole alone
• May 1, 2006
  Bolivian president Evo Morales orders military to occupy oil and gas fields in country, placing them under state control
• May 1, 2011
  U.S. President Barack Obama announces that Osama bin Laden, the founder and leader of the militant group Al-Qaeda, has been killed during an American military operation in Pakistan

April 14

• April 14, 1792
  After declaration issued by Holy Roman Emperor Leopold II and Frederick William II of Prussia against the French Revolution, France declares war on Austria, starting French Revolutionary Wars which lead into the Napoleonic Wars
• April 14, 1841
  American author Edgar Allan Poe publishes his short story "The Murders on the Rue Morgue", considered the first detective
• April 14, 1847
  Persia and Ottoman Empire sign second Treaty of Erzurum, settling boundary disputes between countries
• April 14, 1853
  Harriet Tubman, an African-American abolitionist, begins her Underground Railroad, a network of secret routes to help slaves to escape
• April 14, 1859
  Charles Dickens' "A Tale Of Two Cities" is published
• April 14, 1860
  First Pony Express rider arrive in San Francisco with mail originating in St. Joseph, Missouri
• April 14, 1865
  John Wilkes Booth, an actor and Confederate sympathizer, fatally shoots US President Abraham Lincoln at a play at Ford's Theater in Washington, D.C.; Andrew Johnson becomes 17th President of the United States
• April 14, 1894
  Thomas Edison makes his first public showing of the kinetoscope in New York City showing moving pictures through a magnifying lens
• April 14, 1900
  French President Emile Loubet opens International Fairs in Paris, France
• April 14, 1912
  RMS Titanic, a British passenger liner, sinks in the North Atlantic after hitting with an iceberg during her maiden voyage which causes the deaths of 1,502 people
• April 14, 1927
  In Sweden, Volvo produces its first production line car, Volvo OV 4, in Gothenburg, which has a 28-hp 4-cylinder engine, and costs 4800 kronor
• April 14, 1931
  The Second Spanish Republic is proclaimed in Madrid, Spain after King Alfonso XIII left the country following municipal elections
• April 14, 1935
  The great dust storm in the United States hits eastern New Mexico and Colorado, and western Oklahoma the hardest, which greatly damages the ecology and agriculture and forces tens of thousands of families to abandon their farms
• April 14, 1978
  Thousands of Georgians demonstrate against an attempt by Soviet authorities to change the constitutional status of the Georgian language
• April 14, 2003
  The Human Genome Project, an international scientific research project, is successfully completed, with 99 percent of the human genome sequenced to 99.99 percent accuracy
• April 14, 2010
  In Iceland, a volcano buried under the Eyjafjallajokull glacier erupts, sending up a massive ash cloud that prompts the closure of airports in parts of Europe