August 14

• August 14, 554
  Ravenna becomes the seat of the Byzantine governor of Italy, the Exarch
• August 14, 582
  Death of Tiberius II Constantine, emperor of Byzantine
• August 14, 1248
  The foundation stone of Cologne Cathedral, the Gothic church with the largest facade in the world, is laid by Archbishop of Cologne Konrad von Hochstaden
• August 14, 1281
  Typhoon destroys Mongol fleet off the coast of Japan during the second Mongol attempt to conquer Japan
• August 14, 1385
  Portuguese under John I of Portugal defeat Castilians at Aljubarrota and regained independence from Crown of Castile
• August 14, 1385
  Union of Krewo, an act between Poland and Lithuania by which Jogaila, Grand Duke of Lithuania, converts to Christianity in exchange for marriage to the underage reigning Queen Jadwiga of Poland, is signed in Kreva Castle, modern-day Belarus
• August 14, 1457
  Gutenberg's financier Johann Fust and calligrapher Peter Schöffer publish Mainz Psalter, the second major book printed with movable type in the West
• August 14, 1498
  Columbus lands at the mouth of the Orinoco River in Venezuela, a continental landmass of South America
• August 14, 1756
  French commander Louis-Joseph de Montcalm takes Fort Oswego, New England, from the British
• August 14, 1784
  Three Saints Bay, the first Russian settlement in Alaska is established on Kodiak Island by Russian fur trader Grigory Shelikhov
• August 14, 1790
  Sweden and Russian come to peace at Värälä, by which neither side gains any territory and Russia agrees to not interfere with Sweden's constitution
• August 14, 1791
  Haitian slaves, led by voodoo priest Dutty Boukman, gather to plan a revolution
• August 14, 1793
  Republican troops in France lay siege to the city of Lyon
• August 14, 1816
  Great Britain annexes Tristan da Cunha, a group of volcanic islands in the south Atlantic Ocean
• August 14, 1842
  Seminole War ends as Indians remove from Florida to Oklahoma and United States officer William Worth declares the war to be at an end
• August 14, 1880
  Construction of Cologne Cathedral, begun in 1248, is completed
• August 14, 1893
  Paris Police Ordinance, France, issues first driving licenses, includes required test
• August 14, 1900
  Eight-Nation Alliance successfully storm and occupy Beijing after about 2 months of siege of the city during the Boxer Rebellion
• August 14, 1935
  The Social Security Act, signed by United States President Franklin Delano Roosevelt, creates the Social Security system and introduces federal assistance for the elderly
• August 14, 1941
  US President Franklin Roosevelt and British Prime Minister Winston Churchill create the Atlantic Charter, the basis for their wartime alliance, pledging to seek to gain no territory and desire no territory changes outside of the choices of people
• August 14, 1947
  The Muslim majority region, formed by the Partition of India, gain independence from the British Empire as Dominion of Pakistan, which results in the largest mass migration in human history
• August 14, 1971
  Bahrain declares its independence from Britain
• August 14, 1971
  British begin internment without trial in Northern Ireland

August 12

• August 12, 30 BC
  Cleopatra, the most famous queen and the last active pharaoh of Ancient Egypt, kills herself by inducing an Egyptian cobra to bite her after her beloved Mark Antony's suicide
• August 12, 1093
  In England the foundation stone for Durham Cathedral is laid down
• August 12, 1332
  Rebels supporting the Balliol beat forces of the infant David II, the son of Robert the Bruce at the Battle of Dupplin Moor in Scotland
• August 12, 1399
  Battle of the Vorskla River, a major battle between joint armies of Tokhtamysh and Grand Duke Vytautas of Lithuania, and the Tatars, under Edigu and Temur Qutlugh, ends in a decisive Tatar victory
• August 12, 1508
  Juan Ponce de León, a Spanish explorer, arrives to New World to conquer the Puerto Rico
• August 12, 1648
  Seven-year-old Mehmed IV succeeds Ibrahim in the Ottoman House of Osman
• August 12, 1687
  At the Battle of Mohács, Hungary, the forces of Holy Roman Emperor Leopold I, commanded by Charles of Lorraine defeated the Turks
• August 12, 1759
  Forces of Frederick the Great are defeated by combined army of Russians and Austrians under Pyotr Saltykov at Kunersdorf, which gives the victors the opportunity to march against Berlin
• August 12, 1812
  British commander the Duke of Wellington occupies Madrid, Spain, forcing out Joseph Bonaparte
• August 12, 1851
  Isaac Singer, the founder of the Singer Sewing Machine Company, is granted a patent for his sewing machine
• August 12, 1883
  The last quagga, subspecies of the plains zebra, dies at the Artis Magistra zoo in Amsterdam
• August 12, 1896
  Gold is discovered at Dawson on the Klondike River in Alaska, triggering Klondike Gold Rush in Canada
• August 12, 1981
  At the Waldorf-Astoria Hotel in New York City, and in Boca Raton, Florida, IBM announces the model 5150, called IBM Personal Computer, a progenitor of the IBM PC compatible hardware platform
• August 12, 1982
  Mexico announces it is unable to pay its large foreign debt, triggering a debt crisis that quickly spreads throughout Latin America
• August 12, 1985
  Japan Airlines Flight 123 crashes in Japan, killing 520 people becoming the worst single-aircraft disaster in history
• August 12, 1990
  The largest and most complete skeleton of a Tyrannosaurus rex, called "Sue", is discovered near Faith, South Dakota
• August 12, 2000
  The Russian submarine K-141 Kursk sinks in the Barents Sea, resulting in the deaths of all 118 men on board

June 21

• June 21, 217 BC
  Roman army is ambushed and destroyed by Hannibal's army, numbering around 55,000 troops, at the Battle of Lake Trasimene, which becomes the largest ambush in military history
• June 21, 1377
  Edward III, King of England, dies
• June 21, 1547
  The great fire in Moscow destroys sections of Moscow which had been built almost entirely of wood including some building in the Kremlin
• June 21, 1607
  The Church of England Episcopal Church, the first Protestant Episcopal parish in America, is established at Jamestown
• June 21, 1661
  Sweden signs the Treaty of Cardis, in which Russia agrees to return to Sweden areas it had conquered in the Baltic lands
• June 21, 1675
  Sir Christopher Wren begins to rebuild St Paul's Cathedral in London, replacing the old building which has been destroyed by the Great fire
• June 21, 1749
  English transport ships land 2576 colonists on what is now Nova Scotia to establish a British military base, naming the town Halifax
• June 21, 1788
  New Hampshire ratifies the United States Constitution as the ninth state, and by the terms of Article VII it is in effect
• June 21, 1834
  Obed Hussey, an American inventor, patents mechanical reaping machine
• June 21, 1887
  Britain celebrates the golden jubilee of Queen Victoria
• June 21, 1893
  George Washington Gale Ferris, engineer, completes the construction of a 77-meter high revolving steel wheel with 38 passenger cars, each with 40 plush chairs, for the World's Columbian Exposition in Chicago, the first Ferris wheel
• June 21, 1897
  In Austria a giant Ferris wheel, designed by Walter Bassett of England, is opened in Vienna to commemorate the 50th anniversary of the accession of Emperor Franz Joseph to the Habsburg throne
• June 22, 1940
  After German blitz France formally surrenders at the signing ceremony, held in the same wagon-lit railroad car used by French Marshal Ferdinand Foch to accept the surrender of Germany in 1918
• June 21, 1948
  In a lab in Manchester, England, the Small Scale Experimental Machine computer, nicknamed "Baby" is created, the first to contain memory (128 bytes) which could store a program
• June 21, 1985
  It is confirmed by American, German, and Brazilian forensic pathologists that the body exhumed in Brazil on June 6 is, indeed, that of the German physician in Auschwitz concentration camp, Josef Mengele

June 11

• June 11, 1719
  Spanish attempt to restart the Jacobite rebellion fails after Scottish rebels, aided by Spanish troops, who are defeated at Glen Shiel surrender
• June 11, 1727
  George I dies on a journey to Hanover, George II becomes king of England
• June 11, 1742
  Austria cedes most of Silesia to Prussia by Treaty of Breslau, ending the First Silesian War
• June 11, 1770
  Captain James Cook, commander of the British ship Endeavour, discovers the Great Barrier Reef off Australia by running onto it
• June 11, 1795
  In Tripoli Pasha Yusuf Karamanli deposes his older brother Hamet in a bloodless coup in Ottoman Tripolitania
• June 11, 1798
  Napoleon captures Malta on his way to Egypt and expels the Knights Hospitaller of Malta from their base
• June 11, 1858
  Saint Isaac's Cathedral, the largest orthodox basilica, built by the French-born architect Auguste de Montferrand in Saint Petersburg, is opened
• June 11, 1898
  Guangxu Emperor of China began Hundred Days' Reform in effort to modernize China, but conservative forces soon squelch the attempt
• June 11, 1901
  Cook Islands are annexed and proclaimed part of New Zealand
• June 11, 1935
  Edwin Armstrong demonstrates FM broadcasting, broadcasting technology that uses the encoding of information in a carrier wave by varying the instantaneous frequency of the wave, for the first time
• June 11, 1963
  Thich Quảng Duc, Buddhist monk, immolates himself on a street in Saigon as a protest against the persecution of Buddhists by the South Vietnamese government
• June 11, 1975
  A democratic and republican Constitution of Greece is promulgated
• June 11, 2008
  Fermi Gamma-ray Space Telescope is launched
• June 11, 2009
  The World Health Organization declares the H1N1 influenza has reached the pandemic level, the first time it has called a global flu epidemic in 41 years