| 14 September 1321 | Italy [births and deaths] | Dante Alighieri, Italian poet, prose writer, moral philosopher, and political theorist, author of Divina commedia/Divine Comedy, dies in Ravenna, Italy (56). |
| 14 September 1829 | Russian Empire, Ottoman Empire, Greece, Serbia [treaties] | The Treaty of Adrianople ends the Russo-Ottoman War and the Greek War of Independence. Sultan Mahmud II of the Ottoman Empire recognizes the London Protocol of March 1829 which guarantees the territory of Greece and the independence of the Danubian provinces (Moldavia and Wallachia) and of Serbia. Russia obtains land south of the Caucasus. |
| 14 September 1851 | USA [births and deaths] | James Fenimore Cooper, US novelist who wrote of life on the frontier, dies in Cooperstown, New York (61). |
| 14 September 1852 | England [births and deaths] | Arthur Wellesley, Duke of Wellington, British army commander and Tory prime minister 1828–30, dies in Walmer Castle, Kent, England (83). |
| 14 September 1854 | UK, France, Russian Empire [Crimean War (1854–56)] | Britain and France land unopposed in the Crimea to begin the Crimean War with Russia over its attempt to increase its power in southeast Europe at the expense of the Ottoman Empire. |
| 14 September 1883 | USA [births and deaths] | Margaret Sanger, US birth control advocate who opens the first birth control clinic in the USA, born in Corning, New York (–1966). |
| 14 September 1908 | USA [companies and organizations] | William C Durant of the Buick Motor Company forms the General Motors Company in Detroit, Michigan, as the basis for establishing a conglomerate of car-building companies. |
| 14 September 1911 | Russian Empire [terrorism] | The Russian prime minister, Peter Stolypin, is assassinated by a revolutionary, and on 19 September the moderate Vladimir Kokovtsov is appointed prime minister. |
| 14 September 1939 | USA [aircraft] | The first effective helicopter, the VS-300, designed by Ukranian-born US engineer Igor Sikorsky, makes its first test flight. |
| 14 September 1939 | China, Japan [Sino–Japanese War (1933–40)] | Japanese troops advance south towards the Chinese port of Changsha, but are repulsed. This ends Japanese expansion in central China until 1944. |
| 14 September 1959 | USSR [space exploration] | The Soviet spacecraft Luna 2 (launched on 12 September) becomes the first spacecraft to strike the Moon. |
| 14 September 1982 | Lebanon [law and government] | The president-elect of Lebanon, Bashir Gemayel, is killed in a Beirut bomb explosion. His brother Amin is sworn in as president on September 23. |
| 14 September 1984 | South Africa [law and government] | The South African prime minister, P W Botha, is sworn in as the country's first executive president. On 17 September, the first 19-member multiracial cabinet is sworn in. |
| 14 September 2003 | Sweden [banking and finance] | Swedish voters reject a proposal to adopt the European Union (EU) single currency, the euro, by 56% to 42% in a referendum, despite widespread support for the move among Sweden's political establishment and industrial sector. Of the EU's 15 current member states, only Sweden, the UK, and Denmark remain outside the euro zone. |
