| 9 December 1437 | Holy Roman Empire, Hungary, Austria, Bohemia [administration] | Unrest follows the death of the Holy Roman Emperor, Sigismund, when he is succeeded as king of Hungary by Albert V, duke of Austria, and the Bohemians refuse to accept Albert as their king. |
| 9 December 1608 | England [births and deaths] | John Milton, English poet, scholar, historian, and republican whose best-known work is Paradise Lost (1667), born in London, England (–1674). |
| 9 December 1625 | UK, United Netherlands, Denmark-Norway [treaties] | By the Treaty of The Hague, England and the United Netherlands join King Christian IV of Denmark and Norway in an anti-Habsburg coalition. |
| 9 December 1687 | Hungary, Ottoman Empire, Holy Roman Empire [administration] | The Holy Roman Emperor Leopold I's son Archduke Joseph is crowned as king of Hungary. The coronation brings to an end the negotiations at Pressburg in which a diet (assembly) of the Hungarian Estates has renounced its rights of resistance and recognized the Hungarian crown as a hereditary possession of the male line of Habsburgs. |
| 9 December 1854 | England, Russia [poetry] | The English poet Alfred, Lord Tennyson, publishes his poem ‘The Charge of the Light Brigade’, a poetic description of the disastrous attack on October 25 1854 by the Light Brigade at the Battle of Balaclava, during the Crimean War. |
| 9 December 1917 | Romania, Germany, Austria-Hungary [treaties] | Romania signs an armistice with the Central Powers at Focsani, Romania. |
| 9 December 1935 | UK, France, Ethiopia, Italy [diplomacy] | Britain's foreign minister, Sir Samuel Hoare, signs an agreement with the French prime minister, Pierre Laval, for the partitioning of Ethiopian territory between Ethiopia and Italy. The Hoare–Laval Plan is denounced in both countries, and is disowned by the British prime minister, Stanley Baldwin. |
| 9 December 1941 | UK [everyday life] | The National Service Bill in the UK lowers the age of call-up to 18½ and renders single women aged 20–30 liable to military service. |
| 9–10 December 1941 | Malaya [World War II (1939–45)] | Japanese aircraft sink the British battleship Prince of Wales and battlecruiser Repulse off the east coast of Malaya, leaving the Allies with no active battleship in the Pacific and severely weakening the defences of Singapore. |
| 9 December 1961 | Tanganyika [decolonization] | Tanganyika becomes an independent state within the British Commonwealth. |
| 9 December 1962 | Tanganyika [administration] | Tanganyika (now Tanzania) becomes a republic within the Commonwealth, with Julius Nyerere as president. |
| 9–10 December 1991 | Europe, Netherlands, UK [treaties] | A summit of European Community heads of government in Maastricht, the Netherlands, agrees the Maastricht Treaty on closer economic and political union (Britain obtains the right to abstain from social legislation and a single currency). |
| 9 December 1992 | UK [political events] | The separation of Charles and Diana, Prince and Princess of Wales, is announced in Britain. |
