| 1178 | BC | Odysseus returned to Ithaka [Astron] |
| 0 | | Feast of St. Benedict Joseph Labre, Patron of Bachelors, Beggars, and Hoboes, and that of St. Drogo, Anchorite, Patron of Baume-les-Messieurs, Fleury-sur-Loire, coffee house owners and workers, the deaf, and the mentally ill |
| 556 | | Election of Pope Pelagius I (556-561) |
| 1071 | | Robert the Weasel captures Bari from the Byzantines after a three year siege |
| 1444 | | Truce of Tours: pause in the Hundred Years' War (1444-1450) |
| 1746 | | the Duke of Cumberland defeated the Jacobites at Culloden, with great slaughter -- Learn More |
| 1777 | | Battle of Bennington: Molly Stark does not "find herself a widow" |
| 1796 | | Battle of Ceva, Day 1: French v. Austro-Piedmontese |
| 1797 | | Royal Navy "mutiny" at Spithead (ends May 14) |
| 1799 | | Battle of Mt. Tabor: Bonaparte's French defeat the Turks in Palestine |
| 1809 | | Battle of Sacile: The Austrians defeat the French |
| 1810 | | Notorious "War Hawk" Rep. Nathaniel Macon of North Carolina proposes "the whole army ought to be abolished" |
| 1818 | | Rush-Bagot treaty ratified, creating an unfortified US-Canada border |
| 1862 | | Abolition of slavery in the District of Columbia |
| 1862 | | Confederate Conscription Act: extends all prior enlistments for the duration and introduces mandatory service for white men 18-35, with exemptions for slaveowners and some others |
| 1865 | | Battles of Columbus & West Point, Ga |
| 1916 | | The French Army forms the Escadrille Americaine. |
| 1917 | | Lenin arrives at the Finland Station, in Petrograd, to plot the Bolshevik Revolution |
| 1924 | | Navy begins relief operations for Mississippi Valley floods (to June 16) |
| 1925 | | Bulgarian Communists blow up St Nedelya Cathedral in Sofia during the funeral of General Konstantin Georgiev, who had been murdered days before; 150 die, including many political and military officials, c. 500 injured |
| 1938 | | Britain recognizes the Italian annexation of Abyssinia |
| 1942 | | Burma: Japanese troops occupy Magwe |
| 1942 | | Philippines: Japanese troops land on Panay |
| 1942 | | A test mobilization of the New York Guard puts 17,000 militiamen on active duty for one day |
| 1944 | | US begins planning "Operation Olympic" - the invasion of Japan. |
| 1945 | | 77th Inf Div lands on Ie Shima, off Okinawa |
| 1945 | | The Red Army initates the Battle of Berlin |
| 1945 | | US troops enter Nuremberg |
| 1945 | | USS 'Laffey' (DD-724) survives six kamikaze hits, off Okinawa |
| 1946 | | US launches captured V-2 rocket, White Sands, NM |
| 1947 | | Congress grants Navy Nurses full commissioned status |
| 1947 | | Nitrate-laden ship explodes at Texas City, over 500 die. |
| 1965 | | Test flight of the Saturn S-1C rocket |
| 1966 | | The Apartheid regime of Rhodesia breaks diplomatic relations with Britain |
| 2007 | | a mass shooter at Virginia Tech left 32 people dead and 17 injured before committing suicide. |