On this day: 15 August

Arab–Byzantine wars: The Battle of Yarmouk between the Byzantine Empire and the Rashidun Caliphate begins.

Arab–Byzantine wars: Maslama ibn Abd al-Malik begins the Second Arab Siege of Constantinople, which will last for nearly a year.

Forces of the Umayyad Caliphate abandoned a year-long siege of Constantinople, ending their goal of conquering the Byzantine Empire.

Carloman, mayor of the palace of Austrasia, renounces his position as majordomo and retires to a monastery near Rome. His brother, Pepin the Short, becomes the sole ruler (de facto) of the Frankish Kingdom.

The Battle of Roncevaux Pass takes place between the army of Charlemagne and a Basque army.

Noble Erchana of Dahauua grants the Bavarian town of Dachau to the Diocese of Freising.

The Saracens conquer and destroy Taranto.

Holy Roman Emperor Otto II is defeated by the Saracens in the Battle of Capo Colonna, in Calabria.

Starting date of the First Crusade as set by Pope Urban II.

Seljuk Sultan Ghiyath ad-Din Mas'ud enters Baghdad after he besieged it for fifty days and the flight of Abbasid caliph al-Rashid Billah the day before.

The cave city of Vardzia is consecrated by Queen Tamar of Georgia.

Albigensian Crusade: The Cathar stronghold of Carcassonne falls to the crusaders.

The Livonian Brothers of the Sword, a Catholic military order, occupy Tarbatu (today Tartu) as part of the Livonian Crusade.

Spanish Reconquista: The Battle of the Puig between the Moorish forces of Taifa of Valencia against the Crown of Aragon culminates in an Aragonese victory.

The foundation stone of Cologne Cathedral, built to house the relics of the Three Wise Men, is laid. (Construction is eventually completed in 1880.)

Michael VIII Palaiologos was crowned Byzantine emperor in Constantinople.

Mongol invasions of Japan: The Mongolian fleet of Kublai Khan is destroyed by a "divine wind" for the second time in the Battle of Kōan.

The city of Rhodes surrenders to the forces of the Knights of St. John, completing their conquest of Rhodes. The knights establish their headquarters on the island and rename themselves the Knights of Rhodes.

Francesco Sforza, lord of Milan, conquers Lucca.

Pope Sixtus IV consecrates the Sistine Chapel.

Afonso de Albuquerque of Portugal conquers Malacca, the capital of the Malacca Sultanate.

Seven Portuguese armed vessels led by Fernão Pires de Andrade meet Chinese officials at the Pearl River estuary.

Panama City, Panama is founded.

Ignatius of Loyola and six classmates take initial vows, leading to the creation of the Society of Jesus in September 1540.

Asunción, Paraguay is founded.

Arequipa, Peru is founded.

Jesuit priest Francis Xavier comes ashore at Kagoshima (Traditional Japanese date: 22 July 1549).

Imjin War: At the Battle of Hansan Island, the Korean Navy, led by Yi Sun-sin, Yi Ŏkki, and Wŏn Kyun, decisively defeats the Japanese Navy, led by Wakisaka Yasuharu.

Emperor Leopold I and French king Louis XIV agree to an armistice in the truce of Ratisbon.

Seven Years' War: Battle of Liegnitz: Frederick the Great's victory over the Austrians under Ernst Gideon von Laudon.

War of 1812: Potawatomi warriors ambushed a United States Army convoy after it had evacuated Fort Dearborn, in present-day Chicago, and razed the fort.

The Marquis de Lafayette, the last surviving French general of the American Revolutionary War, arrives in New York and begins a tour of 24 states.

Tivoli Gardens, one of the oldest still intact amusement parks in the world, opens in Copenhagen, Denmark.

The Cathedral of Our Lady of Peace in Honolulu, Hawaii is dedicated. Now the cathedral of the Roman Catholic Diocese of Honolulu, it is the oldest Roman Catholic cathedral in continuous use in the United States.

Start of the second part of the Montceau-les-Mines troubles by the Black Band, groups of anarchist miners.

Ordination in Constantinople of Fr. Raphael Morgan, the first African-American Orthodox priest, "Priest-Apostolic" to America and the West Indies.

A military coup against the government of Dimitrios Rallis began in the neighbourhood of Goudi in Athens, Greece.

The Panama Canal opens to traffic with the transit of the cargo ship SS Ancon.

World War I: Beginning of the Battle of Cer, the first Allied victory of World War I.

World War I: The First Russian Army, led by Paul von Rennenkampf, enters East Prussia.

Polish–Soviet War: Battle of Warsaw, so-called Miracle at the Vistula.

The Wizard of Oz premieres at Grauman's Chinese Theater in Los Angeles, California.

Decree for the mass expulsion of ethnic Germans from Crimea issued by the Soviet government.

World War II: Battle of Trahili: Superior German forces surround Cretan partisans, who manage to escape against all odds.

World War II: Allied forces began Operation Dragoon, their invasion of southern France.

Emperor Hirohito broadcasts his declaration of surrender following the effective surrender of Japan in World War II; Korea gains independence from the Empire of Japan.

Jawaharlal Nehru (pictured) took office as the first prime minister of India, a post he held for 16 years.

Founder of Pakistan Muhammad Ali Jinnah is sworn in as first Governor-General of Pakistan in Karachi.

The Republic of Korea was established with Syngman Rhee as its first president.

The First Republic of Korea (South Korea) is established in the southern half of the peninsula.

Republic of the Congo (Brazzaville) becomes independent from France.

Border guard Conrad Schumann flees from East Germany while on duty guarding the construction of the Berlin Wall.

President Fulbert Youlou was overthrown in the Republic of Congo, after a three-day uprising in the capital.

The Woodstock Music & Art Fair opens in Bethel, New York, featuring some of the top rock musicians of the era.

Patricia Palinkas becomes the first woman to play professionally in an American football game.

President Richard Nixon completes the break from the gold standard by ending convertibility of the United States dollar into gold by foreign investors.

Takeo Miki makes the first official pilgrimage to Yasukuni Shrine by an incumbent prime minister on the anniversary of the end of World War II.

Big Ear, a radio telescope at Ohio State University, received a strong, apparently extraterrestrial radio signal that became known as the Wow! signal (printout pictured).

Signing of the Assam Accord, an agreement between representatives of the Government of India and the leaders of the Assam Movement to end the movement.

In South Carolina, Shannon Faulkner becomes the first female cadet matriculated at The Citadel (she drops out less than a week later).

Apple introduces the iMac computer.

The Helsinki Agreement between the Free Aceh Movement and the Government of Indonesia was signed, ending more than 28 years of fighting.

Israel's unilateral disengagement plan to evict all Israelis from the Gaza Strip and from four settlements in the northern West Bank begins.

The Smithsonian announces the discovery of the olinguito, the first new carnivorous species found in the Americas in 35 years.

North Korea moves its clock back half an hour to introduce Pyongyang Time, 81⁄2 hours ahead of UTC.

Russia begins production on the Sputnik V COVID-19 vaccine.

US president Donald Trump meets with Russian president Vladimir Putin in Alaska, the first such summit since the 2022 Russian invasion of Ukraine.