| 5 October 1056 | Holy Roman Empire [political events] | When the Holy Roman Emperor Henry III dies, at Bodfeld, in Saxony, he is succeeded by his six-year-old son Henry IV, with his widow Agnes as regent. |
| 5 October 1285 | France [administration] | King Philip III the Bold of France dies of the plague. He is succeeded by his son, Philip IV the Fair. |
| 5 October 1434 | Florence [political events] | The Florentine banker Cosimo de' Medici returns from exile to Florence, becoming its effective ruler. The oligarchy is overthrown, and his rival the political leader Palla Strozzi is banished. |
| 5 October 1465 | France [wars] | King Louis XI of France is forced to make the Peace of Conflans with the League of the Public Weal, the price being the cession of territory on the Somme to Burgundy, and the grant of the duchy of Normandy to his brother Charles, Duke of Berry. |
| 5 October 1511 | Papal States, Venice, Spain, France, Italy [political events] | Pope Julius II forms a ‘Holy League’ with Venice and King Ferdinand I of Aragon, on the pretext of preserving church unity, in reality to drive the French out of Italy. Ferdinand is to acquire the Spanish kingdom of Navarre, the Pope to recover the Italian cities of Bologna and Ferrara. |
| 5 October 1793 | France [religious freedom] | The revolutionary government in France abolishes Christianity. |
| 5 October 1796 | Spain, UK [French Revolutionary Wars (1792–1801)] | Spain declares war on Britain. |
| 5 October 1882 | USA [births and deaths] | Robert Goddard, US astronautics pioneer who develops modern rockets used for launching spacecraft, born in Worcester, Massachusetts (–1945). |
| 5 October 1902 | [births and deaths] | Ray Kroc, US restaurateur who founded McDonald's fast-food hamburger restaurants, born in Chicago, Illinois (–1984). |
| 5 October 1908 | Bulgaria [political events] | King Ferdinand I of Bulgaria declares Bulgaria's independence from the Ottoman Empire and assumes the title of tsar. |
| 5 October 1910 | Portugal [law and government] | Portugal is proclaimed a republic under Theophila Braga, following the deposition of King Manuel II. |
| 5–16 October 1925 | Switzerland, UK, France, Belgium, Germany, Italy [treaties] | The Locarno Conference in Switzerland drafts a treaty by which Britain, France, Belgium, Italy, and Germany guarantee Germany's western borders, and draws up lesser mutual assistance treaties to stabilize Germany's eastern borders. |
| 5 October 1947 | USA [television] | US president Harry S Truman makes the first presidential address to the nation on television. |
| 5 October 1974 | world [everyday life] | David Kunst successfully completes the first verified around-the-world walk: it has taken him 4 years, 3 months, and 15 days. |
