| 44611 | April 17 | Death | 2015 – Izzat Ibrahim al-Douri, Iraqi field marshal and politician (b. 1942) |
| 44612 | April 17 | Death | 2015 – Francis George, American cardinal (b. 1937) |
| 44613 | April 17 | Death | 2015 – Robert P. Griffin, American soldier, lawyer, and politician (b. 1923) |
| 44614 | April 17 | Death | 2015 – Scotty Probasco, American businessman and philanthropist (b. 1928) |
| 44615 | April 17 | Death | 2015 – Jeremiah J. Rodell, American general (b. 1921) |
| 44616 | April 17 | Death | 2015 – A. Alfred Taubman, American businessman and philanthropist (b. 1924) |
| 44617 | April 17 | Holiday and observance | Christian feast day:Benedict Joseph LabreKateri Tekakwitha (Canada)Stephen HardingApril 17 (Eastern Orthodox liturgics) |
| 44618 | April 17 | Holiday and observance | Earliest day on which Store Bededag or General Prayer Day can fall, while May 13 is the latest observed on the 4th Friday after Easter. (Denmark) |
| 44619 | April 17 | Holiday and observance | Evacuation Day, celebrates the recognition of the independence of Syria from France in 1946. |
| 44620 | April 17 | Holiday and observance | FAO Day (Iraq) |
| 44621 | April 17 | Holiday and observance | Flag Day (American Samoa) |
| 44622 | April 17 | Holiday and observance | Women's Day (Gabon) |
| 44623 | April 17 | Holiday and observance | World Hemophilia Day (International observance) |
| 44624 | April 18 | Event | 796 – King Æthelred I of Northumbria is murdered in Corbridge by a group led by his ealdormen, Ealdred and Wada. The patrician Osbald is placed on the throne, but is within 27 days abdicated. |
| 44625 | April 18 | Event | 1025 – Bolesław Chrobry is crowned in Gniezno, becoming the first King of Poland. |
| 44626 | April 18 | Event | 1506 – The cornerstone of the current St. Peter's Basilica is laid. |
| 44627 | April 18 | Event | 1518 – Bona Sforza is crowned as queen consort of Poland. |
| 44628 | April 18 | Event | 1521 – Trial of Martin Luther begins its second day during the assembly of the Diet of Worms. He refuses to recant his teachings despite the risk of excommunication. |
| 44629 | April 18 | Event | 1689 – Bostonians rise up in rebellion against Sir Edmund Andros. |
| 44630 | April 18 | Event | 1738 – Real Academia de la Historia ("Royal Academy of History") is founded in Madrid. |
| 44631 | April 18 | Event | 1775 – American Revolution: The British advancement by sea begins Paul Revere and other riders warn the countryside of the troop movements. |
| 44632 | April 18 | Event | 1797 – The Battle of Neuwied: French victory against the Austrians. |
| 44633 | April 18 | Event | 1807 – The Harwich ferry disaster occurred near the North Sea port of Harwich on the Essex coast (England) in which 60-90 people drowned during the capsizing of a small ferry boat. |
| 44634 | April 18 | Event | 1831 – The University of Alabama is founded. |
| 44635 | April 18 | Event | 1848 – American victory at the battle of Cerro Gordo opens the way for invasion of Mexico. |
| 44636 | April 18 | Event | 1857 – "The Spirits Book" by Allan Kardec is published, marking the birth of Spiritualism in France. |
| 44637 | April 18 | Event | 1864 – Battle of Dybbøl: A Prussian-Austrian army defeats Denmark and gains control of Schleswig. Denmark surrenders the province in the following peace settlement. |
| 44638 | April 18 | Event | 1880 – An F4 tornado strikes Marshfield, Missouri, killing 99 people and injuring 100. |
| 44639 | April 18 | Event | 1897 – The Greco-Turkish War is declared between Greece and the Ottoman Empire. |
| 44640 | April 18 | Event | 1899 – The St. Andrew's Ambulance Association is granted a Royal Charter by Queen Victoria. |