Hans Christian Hohwy was born on 21st September, 1673 in Amsterdam. Larcum Kendall was born on 21st September, 1719 in Charlesbury, Oxfordshire. Jacques-Nicolas Duhamel was born on 21st September, 1777 in Saint-Nicolas d'Aliermont. Nicolas-Thomas Paquet was born on 21st September, 1788 in Saint-Nicolas d'Aliermont. Éléonore-Maxence Lemercier was born on 21st September, 1806 in Saint-Nicolas d'Aliermont. Eugène-Auguste Lefebvre was born on 21st September, 1808 in Saint-Nicolas d'Aliermont. Adeline Huguenin was born on 21st September, 1835 in La Sagne. Jean-Baptiste-Oswald Torchy was born on 21st September, 1840 in Saint-Nicolas d'Aliermont. Constant-Sénateur Queval was born on 21st September, 1848 in Saint-Nicolas d'Aliermont. Marie-Ernestine Grard was born on 21st September, 1863 in Saint-Aubin-le-Cauf.
Hieronymus Cardanus died on 21st September, 1576 in Rom. Adelle Boullard died on 21st September, 1822 in Saint-Nicolas d'Aliermont. Aimée Lejoille died on 21st September, 1874 in Saint-Nicolas d'Aliermont. Gustave-Auguste Perrelet died on 21st September, 1888 in Le Locle.