The Requien Museum owes its name to its creator Esprit Requien (1788 - 1851) who, in 1840, bequeathed his collections and his library to the Calvet Museum. Esprit Requien devoted himself very early on to botany and then to malacology and palaeontology.
Since 1943, the museum has been housed in the 18th century Hôtel Raphaélis de Soissans, which is adjacent to the Musée Calvet. With over 900,000 specimens, it is one of the most important museums in the province. It regularly presents exhibitions. It also houses an important study library and reserves accessible only to researchers.