What is the exact date of Louis Pasteur's birth?

Louis Pasteur was born on 27 December 1822.

He was born in Dole, in the Jura department of eastern France, to Jean-Joseph Pasteur and Jeanne-Étiennette Roqui. His father was a tanner and a former sergeant in Napoleon’s army. The family later moved to Marnoz and then to nearby Arbois, where Pasteur spent much of his childhood.

Pasteur’s early interests included drawing and portraiture, and he was not initially regarded as an outstanding science student. He eventually studied at the Collège Royal de Besançon and the École Normale Supérieure in Paris. His scientific career began in chemistry before expanding into crystallography, fermentation, microbiology, and immunology.

The date is sometimes confused with nearby December dates because Pasteur’s birthday was later celebrated publicly, including a major jubilee at the Sorbonne on 27 December 1892. He died on 28 September 1895, aged 72, and was eventually buried in a crypt at the Pasteur Institute in Paris.