The 21st o September is the 264t day o the year (265t in lowp years) in the Gregorian Calendar, wi 101 days bidin.
- 1415 - Frederick III, Haly Roman Emperor (d. 1493)
- 1452 - Girolamo Savonarola, Italian priest an philosopher (d. 1498)
- 1640 - Philippe o Fraunce, Duke o Orléans (d. 1701)
- 1756 - John Loudon McAdam, Scots ingineer (d. 1832)
- 1817 - John Allan Broun, Scots scientist (d. 1879)
- 1840 - Murad V, Ottoman Sultan (d. 1904)
- 1842 - Abdul Hamid II, Ottoman Sultan (d. 1918)
- 1853 - Heike Kamerlingh Onnes, Dutch pheesicist (d. 1926)
- 1866 - H. G. Wells, Inglis writer (d. 1946)
- 1874 - Gustav Holst, Inglis componer (d. 1934)
- 1876 - William Maxwell, Scots fitbawer an cricketer (d. 1940)
- 1902 - George McLachlan, Scots fitbawer (d. ?)
- 1909 - Kwame Nkrumah, 1st Preses o Ghana (d. 1972)
- 1919 - Mario Bunge, Argentine pheesicist an philosopher (d. 2020)
- 1926 - Donald A. Glaser, American pheesicist (d. 2013)
- 1931 - Larry Hagman, American actor (d. 2012)
- 1934 - Leonard Cohen, Canadian sangster-sangwriter an poet (d. 2016)
- 1934 - David J. Thouless, Scots-American pheesicist (d. 2019)
- 1936 - Yury Luzhkov, Roushie politeecian, umwhile Mayor o Moscow (d. 2019)
- 1947 - Stephen King, American writer
- 1950 - Bill Murray, American actor an comedian
- 1954 - Shinzo Abe, umwhile Prime meenister o Japan
- 1957 - Kevin Rudd, 26t Prime Meenister o Australie
- 1967 - Faith Hill, American sangster
- 1967 - Suman Pokhrel, Nepalese poet
- 1972 - Liam Gallagher, Inglis sangster (Oasis)
- 1979 - Keith Lasley, Scots fitbawer
- 1980 - Kareena Kapoor, Indian actress
- 1981 - Nicole Richie, American fashion designer, author, actress an telly personality
- 1987 - Ross Thomson, Scots politeecian
- 1989 - Jason Derulo, American sangster