| 121321 | October 23 | Birth | 1999 – Joseph Andre Garcia, Filipino actor |
| 121322 | October 23 | Death | 42 BC – Marcus Junius Brutus the Younger, Roman general and politician (b. 85 BC) |
| 121323 | October 23 | Death | 877 – Ignatios of Constantinople (b. 797) |
| 121324 | October 23 | Death | 891 – Yazaman al-Khadim, Arab general and politician |
| 121325 | October 23 | Death | 930 – Emperor Daigo of Japan (b. 885) |
| 121326 | October 23 | Death | 1456 – John of Capistrano, Italian priest and saint (b. 1386) |
| 121327 | October 23 | Death | 1550 – Tiedemann Giese, Polish bishop (b. 1480) |
| 121328 | October 23 | Death | 1581 – Michael Neander, German mathematician and astronomer (b. 1529) |
| 121329 | October 23 | Death | 1616 – Leonhard Hutter, German theologian and academic (b. 1563) |
| 121330 | October 23 | Death | 1688 – Charles du Fresne, sieur du Cange, French philologist and historian (b. 1610) |
| 121331 | October 23 | Death | 1730 – Anne Oldfield, English actress (b. 1683) |
| 121332 | October 23 | Death | 1764 – Emmanuel-Auguste de Cahideuc, Comte Dubois de la Motte, French admiral (b. 1683) |
| 121333 | October 23 | Death | 1774 – Michel Benoist, French missionary and astronomer (b. 1715) |
| 121334 | October 23 | Death | 1867 – Franz Bopp, German linguist and academic (b. 1791) |
| 121335 | October 23 | Death | 1869 – Edward Smith-Stanley, 14th Earl of Derby, English lawyer and politician, Prime Minister of the United Kingdom (b. 1799) |
| 121336 | October 23 | Death | 1872 – Théophile Gautier, French journalist, author, and poet (b. 1811) |
| 121337 | October 23 | Death | 1885 – Charles S. West, American lawyer, jurist, and politician, Secretary of State of Texas (b. 1829) |
| 121338 | October 23 | Death | 1893 – Alexander of Battenberg (b. 1857) |
| 121339 | October 23 | Death | 1910 – Chulalongkorn, Thai king (b. 1853) |
| 121340 | October 23 | Death | 1915 – W. G. Grace, English cricketer and physician (b. 1848) |
| 121341 | October 23 | Death | 1917 – Eugène Grasset, Swiss illustrator (b. 1845) |
| 121342 | October 23 | Death | 1921 – John Boyd Dunlop, Scottish businessman, founded Dunlop Rubber (b. 1840) |
| 121343 | October 23 | Death | 1935 – Charles Demuth, American painter and educator (b. 1883) |
| 121344 | October 23 | Death | 1939 – Zane Grey, American dentist and author (b. 1872) |
| 121345 | October 23 | Death | 1942 – Ralph Rainger, American pianist and composer (b. 1901) |
| 121346 | October 23 | Death | 1943 – Wakashima Gonshirō, Japanese sumo wrestler, the 21st Yokozuna (b. 1876) |
| 121347 | October 23 | Death | 1944 – Charles Glover Barkla, English-Scottish physicist and academic, Nobel Prize laureate (b. 1877) |
| 121348 | October 23 | Death | 1944 – Hana Brady, Czech holocaust victim (b. 1931) |
| 121349 | October 23 | Death | 1950 – Al Jolson, Lithuanian-American actor and singer (b. 1886) |
| 121350 | October 23 | Death | 1953 – Adrien de Noailles, French son of Jules Charles Victurnien de Noailles (b. 1869) |