The Museum Requien owes its name to its creator Esprit Requien (1788 - 1851) who, in 1840, bequeathed to the Calvet Museum its collections and its library. Esprit Requien devoted himself very early on to botany, then to malacology and paleontology.
Since 1943, the museum has been housed in the Raphélis de Soissans hotel (18C) which adjoins the Calvet Museum. With more than 1.2 million specimens, it is one of the most important natural history museums in the region. It regularly presents exhibitions. It also houses a large study library and reserves accessible only to researchers.