Sedhiou was originally a Banyun settlement located at an important river crossing for trade caravans as well as the uppermost limit of the tidal flow of the Casamance.

Upon the establishment of the Kaabu federation it became one of the state's constituent kingdoms, ruled by the Mandinka.

Euro-African traders from Saint-Louis, Goree, and Bathurst increasingly competed with native merchants, creating tensions in surrounding communities.

Muslim Mandinka allied with the Fula of Futa Jallon to attack the animist Mandinka of Sedhiou in 1843, imposing tribute on them, although the war continued for years.

His ally Sounkari, the chief of Bacoum, nevertheless continued the fight and unsuccessfully besieged the French fort in 1882.