| 27 October 939 | Wessex, Mercia, England [political events] | Edmund succeeds o the throne of England following the death of his brother King Athelstan (or Aethelstan or Ethelstan) of England. |
| 27 October 939 | Wessex, Mercia, England [births and deaths] | Athelstan (or Aethelstan or Ethelstan), Anglo-Saxon king of Wessex and Mercia 924–25 and first king of England 925–39, dies in England (c. 44). |
| 27 October 1062 | Holy Roman Empire [administration] | Alexander II is declared to be the true Pope in a synod held at Augsburg, defeating his challenger Honorius II. |
| 27 October 1439 | Holy Roman Empire, Austria, Hungary [administration] | The Holy Roman Emperor Albert II dies. He is succeeded as king of Hungary by King Wladyslaw III (Warnenczyk) of Poland. |
| 27 October 1644 | UK [British Civil Wars (1642–51)] | Parliamentarian forces under Edward Montagu, 2nd Earl of Manchester, William Waller, and Oliver Cromwell fail to capture a small Royalist force under King Charles I at the second Battle of Newbury of the English Civil War, allowing it to escape to Oxford instead. The failure leads directly to the formation of the New Model Army in an attempt to raise standards and create better coordination between various parts of the parliamentarian army. |
| 27 October 1859 | USA [births and deaths] | Theodore (‘Teddy’) Roosevelt, twenty-sixth president of the USA 1901–09, a Republican, born in New York City (–1919). |
| 27 October 1908 | United Kingdom, Germany [diplomacy] | The British Daily Telegraph publishes remarks by Kaiser Wilhelm II of Germany in which he states that the German people are hostile to Britain, though he remains a friend. The statement arouses strong feelings in Germany against Britain, and also against the Kaiser for making policy pronouncements without consulting the German chancellor. |
| 27 October 1932 | [births and deaths] | Sylvia Plath, US poet and novelist, born in Boston, Massachusetts (–1963). |
| 27 October 1951 | UK [administration] | The veteran British Conservative Party leader Winston Churchill forms a government, with Anthony Eden as foreign secretary and R A ‘Rab’ Butler as chancellor of the Exchequer. |
| 27 October 1962 | USA [plays] | The play Who's Afraid of Virginia Woolf?, by the US dramatist Edward Albee, is first performed, at the Billy Rose Theater in New York City. |
| 27 October 1966 | South Africa, South West Africa [United Nations] | The United Nations (UN) Assembly ends South Africa's mandate over South West Africa because of its racial policies, but South Africa refuses to accept the decision. |
| 27 October 1979 | St Vincent and Grenadines, UK [decolonization] | St Vincent and the Grenadines, in the West Indies, gain their independence from Britain. |
| 27 October–14 November 2005 | France [revolution] | In France's worst social unrest for nearly 40 years, rioting and violence in a poor, mainly immigrant suburb of Paris spreads daily over three weeks to towns and cities across the country, highlighting problems of unemployment and ethnic discrimination and forcing the government to declare a state of emergency to regain control of the streets. |