| | 1282 - The people of Sicily rebel against the Angevin king Charles I, in what becomes known as the Sicilian Vespers. |
| | 1296 - Edward I sacks Berwick-upon-Tweed, during armed conflict between Scotland and England. |
| | 1492 - Ferdinand and Isabella sign the Alhambra decree aimed at expelling all Jews from Spain unless they convert to Roman Catholicism. |
| | 1533 - Thomas Cranmer becomes Archbishop of Canterbury. |
| | 1814 - Napoleonic Wars: Sixth Coalition forces march into Paris. |
| | 1822 - Florida Territory created in the United States. |
| | 1842 - Anesthesia is used for the first time in an operation by Dr. Crawford Long. |
| | 1844 - One of the most important battles of the Dominican War of Independence from Haiti takes place near the city of Santiago de los Caballeros. |
| | 1855 - Origins of the American Civil War: Bleeding Kansas - "Border Ruffians" from Missouri invade Kansas and force election of a pro-slavery legislature. |
| | 1856 - The Treaty of Paris (1856) is signed, ending the Crimean War. |
| | 1858 - Hymen Lipman patents a pencil with an attached eraser. |
| | 1867 - Alaska is purchased for $7.2 million, about 2 cent/acre ($4.19/km²), by United States Secretary of State William H. Seward. The news media call this Seward's Folly. |
| | 1870 - Texas is readmitted to the Union following Reconstruction. |
| | 1910 - Mississippi Legislature founded The University of Southern Mississippi. |
| | 1912 - Sultan Abdelhafid signs the Treaty of Fez, making Morocco a French protectorate. |
| | 1940 - Sino-Japanese War: Japan declares Nanking to be the capital of a new Chinese puppet government, nominally controlled by Wang Ching-wei. |
| | 1945 - World War II: Soviet Union forces invade Austria and take Vienna, Polish and Soviet forces liberate Gdańsk. |
| | 1951 - Remington Rand delivers the first UNIVAC I computer to the United States Census Bureau. |
| | 1954 - The first subway in Canada opens after five years of construction, in Toronto. |
| | 1961 - The Single Convention on Narcotic Drugs is signed at New York. |
| | 1964 - Merv Griffin's game show Jeopardy! makes its debut on television. Art Fleming hosts the first episode on NBC. |
| | 1965 - Vietnam War: A car bomb explodes in front of the U.S. Embassy in Saigon, killing 22 and wounding 183 others. |
| | 1972 - Vietnam War: The Easter Offensive begins after North Vietnamese forces cross into the Demilitarized Zone (DMZ) of South Vietnam. |
| | 1979 - Airey Neave, a British politician, is killed by a car bomb as he exits the Palace of Westminster. The INLA claims responsibility. |
| | 1981 - President Ronald Reagan is shot in the chest outside a Washington, D.C., hotel by John Hinckley, Jr. |
| | 2006 - Marcos Pontes is the first Brazilian astronaut in space. |
| | 2006 - UK Terrorism Act 2006 becomes law. |