| 25 January 41 | Roman Empire [political events] | Having murdered the Roman emperor Caligula (Gaius Caesar), the soldiers of the Praetorian Guard proclaim Caligula's uncle, Claudius, emperor. |
| 25 January 1340 | Flanders [administration] | King Edward III of England assumes the title of king of France at Ghent, Flanders, and is recognized as such by the Flemings. |
| 25 January 1491 | Poland-Lithuania [wars] | Polish–Lithuanian forces under Jan Olbracht, son of King Casimir (Kazimierz) IV of Poland, decisively defeat the Kazan Tartars at Zaslaw, Poland, gaining respite from their raids. |
| 25 January 1533 | England [political events] | King Henry VIII of England secretly marries his mistress Anne Boleyn; his divorce from Catherine of Aragon is still pending. |
| 25 January 1579 | United Netherlands, Holy Roman Empire [Dutch Revolt (1598–1609)] | Deputies from the northern Dutch provinces of Holland, Zeeland, Utrecht, Gelderland, Friesland, Oomelanden around Groningen, and Zutphen in Overijssel sign a perpetual alliance in Utrecht. The signatories are to act as a single province in war and foreign policy, but retain provincial rights and liberties in religion and other matters. The Union of Utrecht thus forms the foundation of the United Provinces of the Netherlands. |
| 25 January 1627 | Ireland [births and deaths] | Robert Boyle, Anglo-Irish chemist and natural philosopher, who conducted pioneering experiments on the properties of gases, born in Lismore, County Waterford, Ireland (–1691). |
| 25 January 1759 | Scotland [births and deaths] | Robert Burns, national poet of Scotland, born in Alloway, Ayrshire, Scotland (–1796). |
| 25 January 1831 | Poland, Russian Empire [political events] | The Polish diet (national assembly) declares Poland independent of Russia and the rule of the Russian tsars. |
| 25 January 1882 | England [births and deaths] | Virginia Woolf, English author and critic, born in London, England (–1941). |
| 25 January 1900 | South Africa [Anglo–Boer Wars (1899–1902)] | In the Battle of Spion Kop in the Second Anglo-Boer War, a Boer army forces the British troops under General Sir Redvers Buller to retreat with heavy losses. |
| 25 January 1924 | France, Norway, Finland, Austria, USA, Switzerland, Canada, Sweden [Olympic Games] | The 1st Winter Olympic Games open at Chamonix, France, attended by 258 competitors, 13 of whom are women, from 16 nations. Norway and Finland win 4 gold medals each; Austria, 2; and the USA, Switzerland, Canada, and Sweden, 1 each. Clas Thunberg of Finland wins five speed skating medals, including three golds. |
| 25 January 1924 | France, Czechoslovakia [political events] | A French-Czechoslovak alliance is formed; France wishes to create a defensive ring around Germany. |
| 25 January 1947 | USA [births and deaths] | Al Capone, US gangster, dies in Miami Beach, Florida (48). |
| 25 January 1949 | USSR, Bulgaria, Czechoslovakia, Hungary, Poland, Romania, Albania,Yugoslavia [international organizations] | The Council for Mutual Economic Assistance (Comecon) is formed in Moscow to further economic cooperation between the USSR and its satellites (Bulgaria, Czechoslovakia, Hungary, Poland, Romania, and Albania, with Yugoslavia as an associated member). |
| 25 January 1949 | USA [television] | Awards for television are inaugurated in the USA: the first Emmy awards are presented by Walter O'Keefe in Hollywood, California. |
| 25 January 1972 | USA, North Vietnam [Vietnam War (1954–75)] | The US president Richard Nixon reveals that his national security adviser Henry Kissinger has been conducting secret peace negotiations with North Vietnam, during the Vietnam War, since 1969. |
| 25 January 1981 | China [political events] | A show trial in Beijing, China convicts the ‘Gang of Four’ prominent former political leaders of treason. Jiang Qing, widow of Chairman Mao Zedong, receives a suspended death sentence. |
| 25 January 1985 | South Africa [political events] | The South African president P W Botha opens the country's new three-chamber parliament for whites, Indians, and coloureds. |
| 25 January 1991 | USA [statistics and demography] | US federal health officials announce that 100,777 people have died from AIDS since the discovery of the disease in 1981. |
