AD 37 – Roman emperor Caligula accepts the titles of the Principate, entitled to him by the Senate.
193 – Roman Emperor Pertinax is assassinated by Praetorian Guards, who then sell the throne in an auction to Didius Julianus.
364 – Roman Emperor Valentinian I appoints his brother Flavius Valens co-emperor.
1566 – The foundation stone of Valletta, Malta's capital city, is laid by Jean Parisot de Valette, Grand Master of the Sovereign Military Order of Malta.
1776 – Juan Bautista de Anza finds the site for the Presidio of San Francisco.
1794 – Allies under Prince Josias of Saxe-Coburg-Saalfeld defeat French forces at Le Cateau.
1795 – Partitions of Poland: The Duchy of Courland and Semigallia, a northern fief of the Polish–Lithuanian Commonwealth, ceases to exist and becomes part of Imperial Russia.
1801 – Treaty of Florence is signed.
1802 – Heinrich Wilhelm Matthäus Olbers discovers 2 Pallas, the second asteroid ever to be discovered.
1809 – Peninsular War: France defeats Spain in the Battle of Medellín.
1814 – War of 1812: In the Battle of Valparaíso, two American naval vessels are captured by two Royal Navy vessels of equal strength.
1842 – First concert of the Vienna Philharmonic Orchestra, founded by Otto Nicolai.
1854 – Crimean War: France and Britain declare war on Russia.
1860 – First Taranaki War: The Battle of Waireka begins.
1862 – American Civil War: In the Battle of Glorieta Pass, Union forces stop the Confederate invasion of the New Mexico Territory. The battle began on March 26.
1871 – The Paris Commune is formally established in Paris.
1883 – Tonkin Campaign: French victory in the Battle of Gia Cuc.
1910 – Henri Fabre becomes the first person to fly a seaplane, the Fabre Hydravion, after taking off from a water runway near Martigues, France.
1920 – Palm Sunday tornado outbreak of 1920 affects the Great Lakes region and Deep South states.
1933 – The Imperial Airways biplane City of Liverpool is believed to be the first airliner lost to sabotage when a passenger sets a fire on board.
1939 – Spanish Civil War: Generalissimo Francisco Franco conquers Madrid after a three-year siege.
1941 – World War II: Britain's Mediterranean Fleet sinks three heavy cruisers and two destroyers of Italy's Regia Marina.
1942 – World War II: A British combined force permanently disables the Louis Joubert Lock in Saint-Nazaire in order to keep the German battleship Tirpitz away from the mid-ocean convoy lanes.
1946 – Cold War: The United States Department of State releases the Acheson–Lilienthal Report, outlining a plan for the international control of nuclear power.
1951 – First Indochina War: In the Battle of Mạo Khê, French Union forces, led by World War II hero Jean de Lattre de Tassigny, inflict a defeat on Việt Minh forces commanded by General Võ Nguyên Giáp.
1959 – The State Council of the People's Republic of China dissolves the government of Tibet.
1968 – Brazilian high school student Edson Luís de Lima Souto is killed by military police at a protest for cheaper meals at a restaurant for low-income students.
1969 – Greek poet and Nobel Prize laureate Giorgos Seferis makes a famous statement on the BBC World Service opposing the junta in Greece.
1970 – An earthquake strikes western Turkey at about 23:05 local time, killing 1,086 and injuring 1,260.
1978 – The US Supreme Court hands down 5–3 decision in Stump v. Sparkman, a controversial case involving involuntary sterilization and judicial immunity.
1979 – A coolant leak at the Three Mile Island's Unit 2 nuclear reactor outside Harrisburg, Pennsylvania leads to the core overheating and a partial meltdown.
1990 – United States President George H. W. Bush posthumously awards Jesse Owens the Congressional Gold Medal.
1994 – In South Africa, African National Congress security guards kill dozens of Inkatha Freedom Party protesters.
1999 – Kosovo War: Serb paramilitary and military forces kill 146 Kosovo Albanians in Izbica.
2003 – In a friendly fire incident, two American A-10 Thunderbolt II aircraft attack British tanks participating in the 2003 invasion of Iraq, killing one soldier.
2005 – An earthquake shakes northern Sumatra with a maximum Mercalli intensity of VI (Strong), leaving 915–1,314 people dead and 340–1,146 injured.
2006 – Massive protests are mounted against France's First Employment Contract law, meant to reduce youth unemployment.