| 18 August 1227 | Mongol Empire [births and deaths] | Genghis Khan (original name Temüjin), great Mongol military leader who established the Mongol Empire, dies (c. 72). |
| 18 August 1503 | Rome [births and deaths] | Pope Alexander VI (Rodrigo Borgia), pope 1492–1503, notorious for his corruption and worldliness, father of Cesare and Lucretia Borgia, dies in Rome, Italy (c. 72). |
| 18 August 1516 | Papal States, Italy, France [political events] | Pope Leo X and the French king Francis I establish the Concordat of Bologna to resolve the long-standing conflict over the power of the church in France. The king of France is allowed to make ecclesiastical appointment, but the nominations have to be confirmed by the pope; and appeals to Rome from France are restricted. Francis also concedes that the pope is not subject to a general council of the church. |
| 18 August 1572 | France, Spain [political events] | The Huguenot Henri de Bourbon, king of Navarre since the death of his mother Jeanne d'Albret in June, marries Marguerite de Valois, sister of King Charles IX of France – the fruit of the reconciliation between Charles and the French Huguenot commander Admiral Gaspard de Coligny. |
| 18 August 1604 | UK, Habsburg Monarchy, Spain, United Netherlands [treaties] | A peace is signed between England, Spain, and the archdukes, allodial rulers of the Spanish Netherlands; King James I of England will give no further aid to the United Netherlands, will work to promote its submission to Spain and the archdukes, and will permit recruitment for the Spanish Habsburg Army of Flanders. England receives various trading privileges but undertakes not to trade in the West Indies. |
| 18 August 1700 | Sweden, Denmark-Norway, United Netherlands, UK [Great Northern War (1700–21)] | Denmark's invasion of the Duchy of Holstein-Gottorp, fulfilling its 1699 treaty obligations to Saxony-Poland and Russia, prompts a Swedish invasion of Denmark and a march on the capital, Copenhagen. After intervention by the United Netherlands and Great Britain, King Charles XII of Sweden and King Frederick IV of Denmark sign the Peace of Traventhal which removes Denmark from the Great Northern War for a period of nine years, and allows the Duke of Holstein-Gottorp, brother-in-law of King Charles XII of Sweden, to build fortifications and to maintain a standing army. |
| 18 August 1765 | Habsburg Monarchy [political events] | The Habsburg heir Joseph II becomes Holy Roman Emperor. His mother, Maria Theresa, ruler of the hereditary Habsburg lands, accepts Joseph as co-regent in the Habsburg Monarchy as a means of maintaining her dominance over him. |
| 18 August 1850 | France [births and deaths] | Honoré de Balzac, French novelist whose writings helped establish the modern form of the novel, dies in Paris, France (51). |
| 18 August 1896 | Madagascar [colonization] | France annexes Madagascar, whose external treaties with other states are annulled. |
| 18 August 1959 | UK [motor vehicles] | The Mini Minor car, designed by Alec Issigonis for the British Motor Corporation, is launched in Britain, costing less than £500. By 1965, one million Minis will have been produced, and the car becomes a symbol of ‘swinging London’ in the late 1960s. |
| 18 August 1971 | Australia, New Zealand, Vietnam [Vietnam War (1954–75)] | Australia and New Zealand announce the withdrawal of their forces from the Vietnam War. |
| 18 August 1977 | China [law and government] | The 11th Chinese Communist Party Congress indicates a swing away from hardline Maoism towards economic improvement. |
| 18–19 August 2004 | [business and economics] | Google, the world's largest Internet web search engine, makes its stock market debut after its initial public offering (IPO) is approved by the US Securities and Exchange Commission. However, it cuts the price range for its IPO and the number of shares for sale, valuing the company at about US$23 billion rather than the US$35 billion previously anticipated. |
