August 27

• August 27, 1626
  Danish forces and allies are soundly defeated at Lutter-am-Barenberg by an army of the Catholic League under Czech leader Wallenstein, marking the end of Danish intervention in European wars
• August 27, 1689
  Peter the Great takes power from his half-sister Sophia and assumes Russian throne, starting politics of modernization and westernization of traditionalist social systems
• August 27, 1776
  The Americans are defeated by the British at the Battle of Long Island, New York
• August 27, 1783
  The first unmanned hydrogen balloon flight, made by Jacques Charles, successfully completes its flight in Paris reaching 900 meter altitude
• August 27, 1813
  Napoleon defeat The Allies at the Battle of Dresden
• August 27, 1849
  Venice, under Daniele Manin, surrender to Austrians under Field Marshal Radetzky, following a siege since July 20 after proclaiming independence
• August 27, 1883
  Explosion of volcano with a force of 1,300 megatons on the island Krakatoa causes the tidal waves in Indonesia's Sunda Strait, which claims some 36,417 lives in Java and Sumatra
• August 27, 1896
  Zanzibar loses to England in a 38-minute war, the shortest war in history, which begins after the death of the pro-British Sultan Hamad bin Thuwaini and the succession of Sultan Khalid bin Barghash
• August 27, 1913
  Lieutenant Peter Nestrov, of Imperial Russian Air Service, performs a loop in a monoplane at Kiev, the first aerobatic maneuver in an airplane
• August 27, 1928
  Kellogg–Briand Pact is signed by the USA, Belgium, Czechoslovakia, Great Britain, Germany, Italy, Japan, and Poland, renouncing war as an instrument of national policy in relations with one another
• August 27, 1939
  Heinkel He 178, the world's first aircraft to fly under turbojet power, makes the first flight, piloted by Erich Warsit

June 15

• June 15, 1094
  El Cid aka Rodrigo Díaz de Vivar, a Castilian nobleman and military leader, with a combined Christian and Moorish army conquest Valencia and becomes the ruler of Taifa of Valencia
• June 15, 1184
  King Magnus V of Norway is defeated by his rival, Sverre
• June 15, 1215
  King John of England affixes his royal seal to the Magna Carta, granting his barons more liberty and asserting the supremacy of the law over the king
• June 15, 1389
  Ottoman army under Murad I defeats Serbian army at the battle of Kosovo completing conquest of Serbia
• June 15, 1467
  Philip the Good Duke of Burgundy, dies at age 76
• June 15, 1658
  Aurangzeb, son of Mughal Emperor Shah-Jahan-e-Azam, deposes and imprisons his father, starting his reign lasted for 49 years and considered as an apex of Mughal Empire
• June 15, 1667
  Jean-Baptiste Denys, a French doctor, performs the first animal to human blood transfusion, transfusing nine ounces of blood from a lamb into 15-year-old boy
• June 15, 1703
  The Rákóczi Uprising against the Habsburg Monarchy becomes the first significant attempt to topple the rule of Habsburg Austria over Hungary
• June 15, 1733
  St. Croix island is purchased from the French by the Dutch West India and Guinea Company
• June 15, 1744
  The warship Centurion under British Commodore George Anson returns to England with a treasure
• June 15, 1775
  The Second Continental Congress vote unanimously to appoint George Washington head of the Continental Army
• June 15, 1785
  Two French balloonists, Jean-François Pilâtre de Rozier and Pierre Romain, die in world's first fatal aviation accident during flight across the English Channel
• June 15, 1844
  Charles Goodyear receives patent #3633 for the vulcanization of rubber, his process to strengthen rubber
• June 15, 1846
  The dispute between the United Staes and Great Britain over the Oregon country is settled by treaty, establishing the boundary at the 49th parallel
• June 15, 1878
  First attempt at motion pictures, using 12 cameras, each taking one picture, is done by Eadweard Muybridge to see if all four of a horse's hooves leave the ground at the same time
• June 15, 1888
  Wilhelm II becomes emperor of Germany
• June 15, 1896
  The Meiji Sanriku tsunami, triggered by magnitude 8.5 earthquake, strikes Japan and causes some 27,000 deaths and destroys 170 miles of coastline
• June 15, 1919
  Lieutenant Arthur Whitten Brown and Captain John Alcock complete the first trans-Atlantic non-stop flight, landing in Ireland
• June 15, 2000
  The June 15th North–South Joint Declaration is adopted between leaders of North and South Korea