| 40711 | April 8 | Death | 2015 – David Laventhol, American journalist and publisher (b. 1933) |
| 40712 | April 8 | Death | 2015 – Jean-Claude Turcotte, Canadian cardinal (b. 1936) |
| 40713 | April 8 | Holiday and observance | Birkat Hachama (observed once every 28 years), last in 2009 and next in 2037 (Hebrew) |
| 40714 | April 8 | Holiday and observance | Buddha's Birthday, also known as Hana Matsuri, "Flower Festival" (Japan) |
| 40715 | April 8 | Holiday and observance | Christian feast day:Anne Ayres (Episcopal Church (USA))ConstantinaJulie Billiart of NamurPerpetuusWalter of PontoiseWilliam Augustus Muhlenberg (Episcopal Church (USA))April 8 (Eastern Orthodox liturgics) |
| 40716 | April 8 | Holiday and observance | Earliest day on which Fast and Prayer Day can fall, while April 14 is the latest celebrated on the second Friday in April (Liberia) |
| 40717 | April 8 | Holiday and observance | Feast of the First Day of the Writing of the Book of the Law (Thelema) |
| 40718 | April 8 | Holiday and observance | International Day of the Roma |
| 40719 | April 9 | Event | 193 – Lucius Septimius Severus is proclaimed Emperor by his troops in Illyricum (Balkans). He marches with his army (16 legions) to Rome. |
| 40720 | April 9 | Event | 475 – Byzantine Emperor Basiliscus issues a circular letter (Enkyklikon) to the bishops of his empire, supporting the Monophysite christological position. |
| 40721 | April 9 | Event | 537 – Siege of Rome: The Byzantine general Belisarius receives his promised reinforcements, 1,600 cavalry, mostly of Hunnic or Slavic origin and expert bowmen. He starts, despite shortages, raids against the Gothic camps and Vitiges is forced into a stale |
| 40722 | April 9 | Event | 1241 – Battle of Liegnitz: Mongol forces defeat the Polish and German armies. |
| 40723 | April 9 | Event | 1288 – Mongol invasions of Vietnam: Yuan forces are defeated by Trần forces in the Battle of Bach Dang in present-day northern Vietnam. |
| 40724 | April 9 | Event | 1388 – Despite being outnumbered 16 to 1, forces of the Old Swiss Confederacy are victorious over the Archduchy of Austria in the Battle of Näfels. |
| 40725 | April 9 | Event | 1413 – Henry V is crowned King of England. |
| 40726 | April 9 | Event | 1440 – Christopher of Bavaria is appointed King of Denmark. |
| 40727 | April 9 | Event | 1454 – The Treaty of Lodi is signed, establishing a balance of power among northern Italian city-states for almost 50 years. |
| 40728 | April 9 | Event | 1511 – St John's College, Cambridge, England, founded by Lady Margaret Beaufort, receives its charter. |
| 40729 | April 9 | Event | 1585 – The expedition organised by Sir Walter Raleigh departs England for Roanoke Island (now in North Carolina) to establish the Roanoke Colony. |
| 40730 | April 9 | Event | 1609 – Eighty Years' War: Spain and the Dutch Republic sign the Treaty of Antwerp to initiate twelve years of truce. |
| 40731 | April 9 | Event | 1682 – Robert Cavelier de La Salle discovers the mouth of the Mississippi River, claims it for France and names it Louisiana. |
| 40732 | April 9 | Event | 1782 – American War of Independence: Battle of the Saintes begins. |
| 40733 | April 9 | Event | 1860 – On his phonautograph machine, Édouard-Léon Scott de Martinville makes the oldest known recording of an audible human voice. |
| 40734 | April 9 | Event | 1865 – American Civil War: Robert E. Lee surrenders the Army of Northern Virginia (26,765 troops) to Ulysses S. Grant at Appomattox Courthouse, Virginia, effectively ending the war. |
| 40735 | April 9 | Event | 1867 – Alaska Purchase: Passing by a single vote, the United States Senate ratifies a treaty with Russia for the purchase of Alaska. |
| 40736 | April 9 | Event | 1909 – The U.S. Congress passes the Payne–Aldrich Tariff Act. |
| 40737 | April 9 | Event | 1914 – Mexican Revolution: One of the world's first naval/air skirmishes takes place off the coast of western Mexico. |
| 40738 | April 9 | Event | 1916 – World War I: The Battle of Verdun: German forces launch their third offensive of the battle. |
| 40739 | April 9 | Event | 1917 – World War I: The Battle of Arras: The battle begins with Canadian Corps executing a massive assault on Vimy Ridge. |
| 40740 | April 9 | Event | 1918 – World War I: The Battle of the Lys: The Portuguese Expeditionary Corps is crushed by the German forces during what is called the Spring Offensive on the Belgian region of Flanders. |