- 364 Roman Emperor Valentinian I appoints his brother Flavius Valens co-emperor
- 845 Paris is sacked by Viking raiders, probably under Ragnar Lodbrok, who collects a huge ransom in exchange for leaving
- 1854 Britain and France declare war on Russia during the Crimean War
- 1939 Spanish Civil War ends, Madrid falls to Francisco Franco
- 1946 Cold War: The United States State Department releases the Acheson-Lilienthal Report, outlining a plan for the international control of nuclear power.