Requien published little, but was an important naturalist (especially in the field of plant communities), enthusiastically and widely erudite. Among his extensive scientific contacts, Bentham, Mirbel, Gray, and his old teacher and good friend de Candolle all visited him. He met his kindred spirit and close colleague spirit Fabre in Corsica, introducing him to conchology and botany. Agassiz was a great friend — Requien sent him extensive information on fossil fishes, and joined him on Agassiz’s first visit to Paris. Mérimée and he, as inspectors of ancient monuments, became lifelong close friends, and helped save Avignon’s walls.