390 BC – Roman-Gaulish Wars: Battle of the Allia: A Roman army is defeated by raiding Gauls, leading to the subsequent sacking of Rome.
362 – Roman–Persian Wars: Emperor Julian arrives at Antioch with a Roman expeditionary force (60,000 men) and stays there for nine months to launch a campaign against the Persian Empire.
452 – Sack of Aquileia: After an earlier defeat on the Catalaunian Plains, Attila lays siege to the metropolis of Aquileia and eventually destroys it.
645 – Chinese forces under general Li Shiji besiege the strategic fortress city of Anshi (Liaoning) during the Goguryeo–Tang War.
1195 – Battle of Alarcos: Almohad forces defeat the Castilian army of Alfonso VIII and force its retreat to Toledo.
1290 – King Edward I of England issues the Edict of Expulsion, banishing all Jews (numbering about 16,000) from England; this was Tisha B'Av on the Hebrew calendar, a day that commemorates many Jewish calamities.
1334 – The bishop of Florence blesses the first foundation stone for the new campanile (bell tower) of the Florence Cathedral, designed by the artist Giotto di Bondone.
1342 – Mu'izz al-Din Husayn defeats the Sarbadars in the Battle of Zava.
1389 – France and England agree to the Truce of Leulinghem, inaugurating a 13-year peace, the longest period of sustained peace during the Hundred Years' War.
1391 – Tokhtamysh–Timur war: Battle of the Kondurcha River: Timur defeats Tokhtamysh of the Golden Horde in present day southeast Russia.
1555 – The College of Arms is reincorporated by Royal charter signed by Queen Mary I of England and King Philip II of Spain.
1812 – The Treaties of Orebro ends both the Anglo-Russian and Anglo-Swedish Wars.
1841 – Coronation of Emperor Pedro II of Brazil, on 18 July.
1857 – Louis Faidherbe, French governor of Senegal, arrives to relieve French forces at Kayes, effectively ending El Hajj Umar Tall's war against the French.
1862 – First ascent of Dent Blanche, one of the highest summits in the Alps.
1863 – American Civil War: Second Battle of Fort Wagner: One of the first formal African American military units, the 54th Massachusetts Volunteer Infantry, supported by several white regiments, attempts an unsuccessful assault on Confederate-held Battery Wagner.
1864 – President Abraham Lincoln asks for 500,000 Americans to volunteer for the military.
1870 – The First Vatican Council decrees the dogma of papal infallibility.
1914 – The U.S. Congress forms the Aviation Section, U.S. Signal Corps, giving official status to aircraft within the U.S. Army for the first time.
1921 – MLB’s Babe Ruth achieves 139 home runs and becomes the all-time home run leader.
1925 – Adolf Hitler's personal manifesto Mein Kampf is published.
1936 – An army uprising in Spanish Morocco starts Spanish Civil War.
1939 – After a sneak preview of The Wizard of Oz, producers debated about removing one of the songs because it seemed to slow things down. The song: Over the Rainbow.
1942 – World War II: The Germans test fly the Messerschmitt Me 262 using its jet engines for the first time.
1944 – World War II: Hideki Tōjō resigns as Prime Minister of Japan because of numerous setbacks in the war effort.
1966 – Human spaceflight: Gemini 10 is launched from Cape Kennedy on a 70-hour mission that includes docking with an orbiting Agena target vehicle.
1966 – Australian children's television series Play School airs for the first time, going on to become the longest-running children's show in Australia, and the second longest running children's show in the world after the British program Blue Peter. which first aired on 16 October 1958.
1968 – Intel is founded in Santa Clara, California.
1969 – After a party on Chappaquiddick Island in Massachusetts, Senator Ted Kennedy drives an Oldsmobile off a bridge into a tidal pond, killing his passenger, Mary Jo Kopechne.
1976 – At the 1976 Summer Olympics, Romanian gymnast Nadia Comăneci became the first person in Olympic Games history to be awarded the score of a perfect 10 in gymnastics.
1977 – Vietnam was admitted to the United Nations.
1982 – Two hundred sixty-eight campesinos ("peasants" or "country people") are slain in the Plan de Sánchez massacre in Ríos Montt's Guatemala.
1984 – McDonald's massacre in San Ysidro, California: In a fast-food restaurant, James Oliver Huberty opens fire, killing 21 people and injuring 19 others before being shot dead by police.
1984 – The dismembered body of Swedish prostitute Catrine da Costa is found in Stockholm, the findings later led to a trial that ended in a mistrial for two accused doctors.
1986 – A tornado is broadcast live on KARE television in Minnesota when the station's helicopter pilot makes a chance encounter.
1992 – The ten victims of the La Cantuta massacre disappear from their university in Lima.
1994 – The bombing of the Asociación Mutual Israelita Argentina (Argentine Jewish Community Center) in Buenos Aires kills 85 people (mostly Jewish) and injures 300.
1994 – Rwandan Genocide: The Rwandan Patriotic Front takes control of Gisenyi and north western Rwanda, forcing the interim government into Zaire and ending the genocide.
1995 – On the Caribbean island of Montserrat, the Soufrière Hills volcano erupts. Over the course of several years, it devastates the island, destroying the capital and forcing most of the population to flee.
1995 – Dreaming of You by Selena, released posthumously, became the best-selling Latin album in the United States. It was noted by Billboard magazine as a "historic event" for Latin music.
1996 – Saguenay Flood: Storms provoke severe flooding on the Saguenay River, beginning one of Quebec's costliest natural disasters ever.
1996 – Battle of Mullaitivu: The Liberation Tigers of Tamil Eelam capture the Sri Lanka Army's base, killing over 1200 soldiers.
2007 – Michael Vick, quarterback for the Atlanta Falcons of the National Football League, was indicted on federal charges related to an illegal dogfighting operation. He was subsequently sentenced to 23 months in prison.
2011 – Marine Corps Gen. John R. Allen took over as commander of U.S. and NATO forces in Afghanistan, vowing to keep "relentlessly pressuring the enemy." Allen replaced Army Gen. David Petraeus, who became director of the CIA.
2012 – At least seven people are killed and 32 others are injured after a bomb explodes on an Israeli tour bus at Burgas Airport, Bulgaria.
2012 – Victims of a suicide bomb at Syria's National Security Bureau included Defense Minister Daoud Rajiha, Deputy Defense Minister Assef Shawkat (President Bashar Assad's brother-in-law), former Defense Minister Hassan Turkomani and NSB chief Hisham Ikhtiar.
2013 – The Government of Detroit, with up to $20 billion in debt, files for the largest municipal bankruptcy in U.S. history.
2014 – In a unanimous vote, the U.S. Sentencing Commission approved guidelines under which 46,000 imprisoned federal drug offenders were eligible for reduced sentences.