| 17 April 1492 | Spain [exploration] | Queen Isabella I of Spain contracts to finance a voyage of discovery headed by Christopher Columbus, naming him admiral and viceroy of any discoveries. |
| 17 April 1539 | Holy Roman Empire, Saxony, Germany [political events] | Henry, a German Lutheran, becomes Duke of Saxony on the death of his brother George, a Catholic; all of northern Germany except Brunswick has now become Protestant. |
| 17 April 1610–22 June 1611 | UK, North America [exploration] | The English explorer Henry Hudson, jointly commissioned by the Muscovy and East India Companies to discover a Northwest Passage to the Pacific, explores Hudson Bay, North America, but is cast adrift by a mutinous crew after the voyage becomes aimless. |
| 17 April 1711 | Austria, Habsburg Monarchy, Holy Roman Empire [political events] | When the Holy Roman Emperor Joseph I of Austria, dies, aged 33, he is ultimately succeeded by his brother, Charles III of Spain, as Emperor Charles VI, who thus becomes heir to all the Spanish Habsburg and Austrian Habsburg possessions, but Charles does not leave Spain until September. |
| 17 April 1790 | America, USA [births and deaths] | Benjamin Franklin, American printer, publisher, and inventor who helped to draft the Declaration of Independence and the US Constitution, dies in Philadelphia, Pennsylvania (84). |
| 17 April 1894 | USSR, Ukraine [births and deaths] | Nikita Sergeyevich Khrushchev, first secretary of the Communist Party of the Soviet Union 1953–64 and premier 1958–64, born in Kalinovka, Ukraine in the Russian Empire (–1971). |
| 17 April 1895 | Korea, Japan, China [treaties] | Under the Treaty of Shimonoseki, China and Japan recognize the independence of Korea following war over its status as a Chinese vassal state. |
| 17 April 1917 | France [World War I (1914–18)] | The first in a wave of French army mutinies occurs on the Western Front in protest at the ‘Chemin des Dames’ offensive. A more serious mutiny begins on 29 April, and such mutinies continue until August 1917, ending the French army's capacity to mount offensives. |
| 17 April 1941 | Yugoslavia, Germany [World War II (1939–45)] | Yugoslavia formally surrenders to the invading German forces. |
| 17–20 April 1961 | Cuba, USA [political events] | One thousand five hundred Cuban exiles, trained by US military instructors and supported by the CIA, land on Cuba in the ‘Bay of Pigs’ invasion. An expected sympathetic uprising fails to occur and the invaders are killed or captured. |
| 17 April 1967 | USA [space exploration] | The US spacecraft Surveyor 3 is launched and soft lands on the Moon where it conducts sampling experiments on the lunar soil. It is subsequently visited by astronauts from the Apollo 12 mission. |
| 17 April 1971 | Egypt, Syria, Libya [diplomacy] | Egypt, Syria, and Libya sign the Benghazi Agreement to establish the Federation of Arab Republics that, based on democratic socialism, creates a joint defence policy and pursues a hard-line attitude towards Israel. |
| 17 April 1975 | Cambodia [political events] | Communist Khmer Rouge revolutionaries in Cambodia capture the capital, Phnom Penh, in the civil war between the right-wing government of the Khmer Republic and the National United Front of Cambodia (the former leader Prince Sihanouk and the Khmer Rouge). |
| 17 April 1982 | Canada [diplomacy] | Repatriation of the Canadian constitution (its removal from British law to place it entirely under Canadian control) breaks Canada's last link with the British government. |
