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