August 25

• August 25, 325
  First Council of Nicaea ends with condemnation of Arian Christianity and establishing the doctrine of the Holy Trinity
• August 25, 357
  Julian, Augustus in the Roman Empire, beats the Alamanni tribal confederation under paramount king Chnodomar in the Battle of Strasbourg
• August 25, 383
  Gratian, Emperor of Rome, is murdered
• August 25, 1270
  Louis IX, King of France, dies on The Eighth Crusade, which is decimated by the Plague
• August 25, 1499
  Ottoman fleet defeats Venetians at the Battle of Zonchio
• August 25, 1515
  Spanish conquistadors under Diego Velázquez de Cuéllar founds Havana in island of Cuba
• August 25, 1530
  Ivan the Terrible, the first tsar of Russia, is born
• August 25, 1543
  Portuguese ships land on the Japanese Island of Tanegashima and introduce the arquebus to Japan beginning the Nanban trade period between Portugal and Japan
• August 25, 1580
  Spain defeat Portugal in the Battle of Alcântara, the decisive battle of the Spanish King Philip II for the Portuguese throne
• August 25, 1609
  Galileo demonstrated his first telescope to Venetian lawmakers
• August 25, 1689
  English–allied Iroquois takes Montreal
• August 25, 1758
  The Prussians lose 12,800 men and the Russians lose 18,000 men during Battle of Zorndorf, which ends with inconclusive results
• August 25, 1765
  In protest over the stamp tax, American colonists sack and burn the home of Massachusetts governor Thomas Hutchinson
• August 25, 1776
  David Hume, a Scottish philosopher and historian, dies
• August 25, 1819
  James Watt, a Scottish inventor, dies
• August 25, 1825
  Uruguay, supported by the United Provinces of the Río de la Plata, declares independence from Brazil
• August 25, 1830
  Theatergoers who have just watched a nationalistic opera in Brussels start Belgium revolts against Netherlands
• August 25, 1835
  New York Sun publishes Moon hoax story, a series of six articles about the supposed discovery of life and even civilization on the Moon
• August 25, 1875
  Matthew Webb becomes the first person to swim across the English Channel, traveling from Dover, England, to Calais, France, in 21 hours and 45 min
• August 25, 1900
  Friedrich Nietzsche, a German philosopher, dies
• August 25, 1944
  French General Charles de Gaulle enters liberated Paris
• August 25, 1981
  Voyager 2 makes the closest approach to Saturn
• August 25, 1989
  First close up pictures of Neptune are taken by spacecraft Voyager 2
• August 25, 1991
  Belarus declares independence from Soviet Union and changes the name to the Republic of Belarus