Louis Pasteur was a professor of chemistry in Strasbourg before becoming dean in Lille. He was appointed to the University of Strasbourg in 1848 and became its chair of chemistry in 1852.
Strasbourg was an important turning point in Pasteur’s life. There he met Marie Laurent, daughter of the university’s rector. They married in 1849 and went on to have five children. His work at Strasbourg also established him as a serious academic chemist rather than only a laboratory researcher.
In 1854, Pasteur became dean of the newly established Faculty of Sciences at the University of Lille. Lille’s industrial environment encouraged his interest in fermentation, especially problems affecting beetroot alcohol and other commercial products. Those investigations helped lead to his broader studies of microorganisms, spoilage, and disease.
Paris came later in his career, when he directed scientific studies at the École Normale Supérieure. Lille is therefore associated with his fermentation research and deanship, while Strasbourg is the city linked to his earlier chemistry professorship.