| 15 August 1038 | Hungary [political events] | When Stephen I, first king of Hungary, dies, he is left without a direct heir because his son Imre has already died, so Peter the German, a distant relation by marriage, is elected as his successor. |
| 15 August 1038 | Hungary [births and deaths] | Stephen I, first king of Hungary 1000–38, founder of the Hungarian state, dies in Esztergom, Hungary (c. 61). |
| 15 August 1198 | Italy, Palestine, France [Crusades (1095–1272)] | Pope Innocent III proclaims the Fourth Crusade to recover Jerusalem from the Muslims and offers an indulgence to those who fight the Albigensians (Cathars; members of a heretical Christian sect) in southern France. |
| 15 August 1209 | France, Toulouse [Crusades (1095–1272)] | The southern French town of Carcassonne is taken by the Albigensian crusaders; the Norman crusader Simon IV de Montfort is then elected leader and expropriates land from the Albigensian (Cathar) heretics and their supporters, becoming lord of Béziers and Carcassonne. |
| 15 August 1231 | Khwarizm, Mongol Empire, Seljuk Sultanate of Rum, Georgia [Mongol conquests (1206–1405)] | Jalal-ad-Din, Shah of Khwarizm, is murdered while fleeing a new Mongol invasion. Kay-Qubadh, Sultan of Rum, now occupies Ahlat and Queen Rusudan of Georgia reoccupies the Georgian capital Tbilisi (modern Tbilisi); the Mongols conquer the rest of his shahdom. |
| 15 August 1281 | China, Japan [Mongol conquests (1206–1405)] | A second fleet sent by Kublai Khan, the Mongol emperor of China, to conquer Japan is destroyed by a typhoon in Hakata Bay. The grateful Japanese call it kamikaze (divine wind). |
| 15 August 1308 | Byzantine Empire [political events] | The Byzantine island of Rhodes surrenders to the Knights Hospitallers (a predominantly French order of Latin Christian chivalry). It becomes their headquarters. |
| 15–17 August 1575 | France [French Wars of Religion (1562–80)] | Francis, Duke of Alençon, the brother and heir to King Henry III of France, escapes from court to declare himself, at Dreux on 17 August, in league with Henri I de Bourbon, Prince of Condé, the Huguenot (French Protestant) leader, and the Palatine Calvinist army under Johann Casimir, invading from Germany. |
| 15 August 1658 | Germany, France, Holy Roman Empire [diplomacy] | The Protestant League of Hildesheim joins with the Catholic Rhine League to form the League of the Rhine, the first nondenominational grouping of states within Germany, aimed at securing a balance of power between France and the Holy Roman Empire. It is a triumph for French diplomacy after King Louis XIV had failed to be elected Holy Roman Emperor. |
| 15 August 1684 | France [treaties] | The Truce of Ratisbon (Regensburg) is reluctantly signed by the Holy Roman Emperor Leopold I, preoccupied with the Ottoman War and under pressure from the Dutch. He recognizes King Louis XIV of France's possession of the territories seized as a result of the Chambres de Réunions policy, including Strasbourg and Luxembourg, for a period of 20 years. By this agreement, the territories of France reach their greatest geographical extent to date. |
| 15 August 1771 | Scotland [births and deaths] | Walter Scott, Scottish novelist, poet, historian, and biographer who developed the historical novel, born in Edinburgh, Scotland (–1832). |
| 15 August 1867 | UK [legislation] | The Second Reform Act extends the franchise in Britain and redistributes parliamentary seats to reflect increasing urbanization. The electorate is roughly doubled from 1 to 2 million. |
| 15 August 1888 | Wales [births and deaths] | T(homas) E(dward) Lawrence (‘Lawrence of Arabia’), British scholar, military strategist, and author, born in Tremadoc, Caernarvonshire, Wales (–1935). |
| 15 August 1914 | Panama [canals] | The Panama Canal opens to traffic. One of the world's greatest engineering feats, it is 81.6 km/50.7 mi long and saves 12,800 km/8,000 mi on the trip around South America. It cost $366,650,000 and around six thousand workers died during its construction. |
| 15 August 1945 | USA [World War II (1939–45)] | Rationing of petrol and fuel oil in the USA comes to an end. |
| 15 August 1947 | India, Pakistan, UK [political events] | British rule in India ends after 163 years and the two new independent countries of India and Pakistan are established. Jawaharlal Nehru becomes prime minister of India, and Mohammed Ali Jinnah governor general of Pakistan, with Liaquat Ali Khan as prime minister. |
| 15 August 1948 | South Korea, USA [political events] | The Republic of Korea is proclaimed in the city of Seoul, ending the US military administration of World War II in southern Korea. |
| 15 August 1964 | UK [cricket] | The England cricketer Fred Trueman becomes the first bowler to take 300 Test wickets, in the final Test against Australia at The Oval, London, England. |
| 15 August 1967 | UK [radio] | The British government introduces legislation outlawing pirate radio stations. Radio Caroline continues to broadcast. |
| 15–17 August 1969 | USA [popular music] | Half a million people attend the three-day Woodstock Music and Arts Fair on a farm in New York State. The line-up includes Jimi Hendrix, the Who, Janis Joplin, Jefferson Airplane, and Santana. |
| 15 August 1971 | Bahrain, UK [decolonization] | Bahrain declares its independence from Britain. |
| 15 August 1971 | USA [legislation] | The US president Richard Nixon introduces a ‘New Economic Policy’, effectively ending the 1944 Bretton Woods system. The new policy suspends the conversion of dollars into gold and imposes a 90-day wage freeze and a 10% import surcharge, following the first US trade deficit since 1894. |
| 15 August 1973 | USA, Cambodia, Laos [political events] | US bombing in Cambodia and Laos ends. |
| 15 August 1993 | Paraguay [elections] | Juan Carlos Wasmosy becomes the first elected president of Paraguay since the country's foundation in 1811. |
| 15 August 1995 | Japan [political events] | On the 50th anniversary of the end of World War II, Prime Minister Tomiichi Murayama of Japan expresses a ‘feeling of deep remorse’ and offers a ‘heartfelt apology’ for Japan's actions in the war. |
| 15 August 2007 | Peru [natural disasters] | An earthquake measuring 8.0 on the Richter scale hits the southern coast of Peru, killing around 500 people, injuring more than 1,000 and leaving 100,000 homeless. |
