August 27 is the 239th day of the year (240th in leap years) in the Gregorian calendar. There are 126 days remaining until the end of the year.
410 – The sacking of Rome by the Visigoths ends after three days.
1172 – King Henry II of England crowns his heirs, Henry the Young King and Queen Margaret, but gives them no actual authority.
1557 – The Battle of St. Quentin results in Emmanuel Philibert becoming Duke of Savoy.
1593 – Pierre Barrière fails in his attempt to assassinate King Henry IV of France.
1776 – Battle of Long Island: In what is now Brooklyn, New York, British forces under General William Howe defeat Americans under General George Washington.
1793 – French Revolutionary Wars: The city of Toulon revolts against the French Republic and admits the British and Spanish fleets to seize its port, leading to the Siege of Toulon by French Revolutionary forces.
1798 – Wolfe Tone's United Irish and French forces clash with the British Army in the Battle of Castlebar, part of the Irish Rebellion of 1798, resulting in the creation of the French puppet Republic of Connacht.
1810 – Napoleonic Wars: The French Navy defeats the British Royal Navy, preventing them from taking the harbour of Grand Port on Île de France.
1813 – French Emperor Napoleon I defeats a larger force of Austrians, Russians, and Prussians at the Battle of Dresden.
1832 – Black Hawk, leader of the Sauk tribe of Native Americans, surrenders to U.S. authorities, ending the Black Hawk War.
1859 – Petroleum is discovered in Titusville, Pennsylvania leading to the world's first commercially successful oil well.
1881 – The Georgia hurricane makes landfall near Savannah, Georgia, resulting in an estimated 700 deaths.
1883 – Eruption of Krakatoa: Four enormous explosions destroy the island of Krakatoa and cause years of climate change.
1893 – The Sea Islands hurricane strikes the United States near Savannah, Georgia, killing between 1,000-2,000 people.
1896 – Anglo-Zanzibar War: The shortest war in world history (09:00 to 09:45), between the United Kingdom and Zanzibar.
1914 – World War I: Battle of Étreux: A British rearguard action by the Royal Munster Fusiliers during the Great Retreat.
1916 – World War I: The Kingdom of Romania declares war on Austria-Hungary, entering the war as one of the Allied nations.
1918 – Mexican Revolution: Battle of Ambos Nogales: U.S. Army forces skirmish against Mexican Carrancistas in the only battle of World War I fought on American soil.
1927 – Five Canadian women file a petition to the Supreme Court of Canada, asking, "Does the word 'Persons' in Section 24 of the British North America Act, 1867, include female persons?"
1928 – The Kellogg–Briand Pact outlawing war is signed by fifteen nations. Ultimately sixty-one nations will sign it.
1939 – First flight of the turbojet-powered Heinkel He 178, the world's first jet aircraft.
1942 – First day of the Sarny Massacre.
1943 – World War II: Japanese forces evacuate New Georgia Island in the Pacific Theater of Operations during World War II.
1943 – World War II: Aerial bombardment by the Luftwaffe razes to the ground the village of Vorizia in Crete.
1956 – The nuclear power station at Calder Hall in the United Kingdom was connected to the national power grid becoming the world's first commercial nuclear power station to generate electricity on an industrial scale.
1962 – The Mariner 2 unmanned space mission is launched to Venus by NASA.
\1971 – An attempted coup d'état fails in the African nation of Chad. The Government of Chad accuses Egypt of playing a role in the attempt and breaks off diplomatic relations.
1975 – The Governor of Portuguese Timor abandons its capital, Dili, and flees to Atauro Island, leaving control to a rebel group.
1979 – A Provisional Irish Republican Army bomb kills British retired admiral Lord Mountbatten and three others while they are boating on holiday in Sligo, Republic of Ireland. Shortly after, 18 British Army soldiers are killed in an ambush near Warrenpoint, Northern Ireland.
1980 – A massive bomb planted by extortionist John Birges explodes at Harvey's Resort Hotel in Stateline, Nevada after a failed disarming attempt by the FBI. Although the hotel is damaged, no one is injured.
1991 – The European Community recognizes the independence of the Baltic states of Estonia, Latvia and Lithuania.
2003 – Mars makes its closest approach to Earth in nearly 60,000 years, passing 34,646,418 miles (55,758,005 km) distant.
2003 – The first six-party talks, involving South and North Korea, the United States, China, Japan and Russia, convene to find a peaceful resolution to the security concerns of the North Korean nuclear weapons program.
2006 – Comair Flight 5191 crashes on takeoff from Blue Grass Airport in Lexington, Kentucky bound for Hartsfield–Jackson Atlanta International Airport in Atlanta. Of the passengers and crew, 49 of 50 are confirmed dead in the hours following the crash.
2009 – Internal conflict in Burma: The Burmese military junta and ethnic armies begin three days of violent clashes in the Kokang Special Region.
2011 – Hurricane Irene strikes the United States east coast, killing 47 and causing an estimated $15.6 billion in damage.
