August 20

• August 20, 1191
  Crusader King Richard I executes some 2,700 Muslim prisoners in Acre
• August 20, 1530
  Hayreddin Barbarossa, a Barbary pirate, unites Algeria and Tunisia as military states under the Ottoman caliphate and becomes admiral of the Ottoman fleet
• August 20, 1619
  The first African slaves arrive to North America aboard a Dutch privateer and dock in Jamestown, Virginia, with twenty human captives among its cargo
• August 20, 1672
  Johan de Witt, Grand Pensionary of Holland and key figure in Dutch politics, is assassinated by a carefully organized lynch mob by a shot in the neck, and his naked body is hanged and mutilated beside body of his brother Cornelis de Witt
• August 20, 1745
  Bonnie Prince Charlie occupies Blair Castle, Scotland
• August 20, 1847
  General Winfield Scott wins the Battle of Churubusco, only 8 kilometers away from Mexico City
• August 20, 1860
  Robert O'Hara Burke leads a group of 15 men, 27 camels and 23 horses out of Melbourne on an expedition to cross Australia
• August 20, 1913
  Adolphe Pégoud becomes the first pilot to parachute from an aircraft
• August 20, 1939
  Soviet forces under Lieutenant General Georgi Zhukov successfully counterattack Japanese invaders at Nomanhan in the Mongolian People's Republic on the border with Manchukuo
• August 20, 1940
  Ramón Mercader, agent of Josef Stalin, fatally stabs Leon Trotsky with an ice pick in Mexico City
• August 20, 1956
  The Calder Hall atomic power station begins operation in Cumberland, Great Britain, generating up to 90,000 kilowatts of power and manufacturing plutonium becoming the world's first power station to generate electricity on an industrial scale
• August 20, 2011
  In the Battle of Tripoli, Libyan rebels take control the nation's capital, effectively overthrowing the government of Muammar Gaddafi

July 12

• July 12, 1191
  Crusading army under King of England Richard I Lionheart captures Acre after two-years siege during Third Crusade
• July 12, 1346
  Edward III lands his army on the Normandy beaches unopposed
• July 12, 1536
  Desiderius Erasmus, a Dutch humanist and priest, dies
• July 12, 1543
  England's King Henry VIII marries his sixth and last wife, Catherine Parr
• July 12, 1561
  The Saint Basil's Cathedral in Moscow, begun in 1555, is completed under the reign of Ivan the Terrible to celebrate the conquest of the Khanate of Kazan
• July 12, 1691
  William III defeated the allied Irish and French armies at the Battle of Aughrim, Ireland
• July 12, 1790
  The French Assembly approve a Civil Constitution of the Clergy providing for the election of priests and bishops
• July 12, 1794
  British Admiral Lord Nelson lost his right eye at the successful siege of Calvi, in Corsica
• July 12, 1806
  The Confederation of the Rhine is established from 16 German states, including Principality of Liechtenstein, by Napoleon in Paris
• July 12, 1856
  William Walker, an American, declares himself president of Nicaragua
• July 12, 1864
  President Abraham Lincoln becomes the first standing president to witness a battle as Union forces repelled Jubal Early's army on the outskirts of Washington, D.C
• July 12, 1878
  A Yellow Fever epidemic, which claimed about 20,000 people, begins in New Orleans
• July 12, 1988
  USSR launches Phobos II for Martian orbit
• July 12, 2006
  Israeli troops invade Lebanon beginning 2006 Lebanon War in response to Hezbollah kidnapping two Israeli soldiers and killing three