For most of two centuries, the Fouta Djallon was governed by one of West Africa's notable experiments in Islamic statecraft. The Imamate of Futa Jallon had risen out of a jihad declared in 1725, when Fula scholars and chiefs gathered at the religious center of Fugumba and chose Karamokho Alfa to lead it. The state they built had two capitals, political power at Timbo and spiritual authority at Fugumba, and it endured longer than most. By the 1890s, though, it was one of the last independent states left in the Senegambia region, an island of self-rule in a continent being carved up by European empires reaching inland from the coasts.

Bokar Biro had come to power in 1890 through a coup, taking the throne after killing his own brother and installing loyalists around him. What followed was a see-saw of power struggles in which he more than once lost his position and clawed it back. The imamate had long alternated rule between two factions, the Alfaya and the more militarist Soriya, and that arrangement had become a fault line. When the French came demanding a treaty that would shut out their British rivals, they found a state already strained from within, its chiefs divided over how, or whether, to resist the outsiders gathering at the borders.

At the end of the 1896 rainy season the French moved, dispatching columns from Senegal, Guinea, and the Sudan to converge on the Fouta Djallon. On 3 November they took Timbo, the political capital. Bokar Biro could not rally the chiefs to his side. On 13 November he gave battle anyway on the plain of Porédaka, facing French troops and Fula auxiliaries led by his rival Umaru Bademba Barry. The ground was poorly chosen and the weapons were unequal: Bokar Biro's men carried muskets of short range and poor make, while the French tirailleurs cut them down from a distance they could not answer. In about an hour it was over. Roughly 150 of his men lay dead and 300 wounded; the French counted three lightly hurt.

Bokar Biro died on that field, and his son died with him. With them died the independence of the Imamate of Futa Jallon, a state that had governed these highlands since 1725. The French installed a resident at Timbo, rewarded the chief Alfa Yaya for his support, and made Umaru Bademba almami, a ruler now serving the empire rather than the imamate. A protectorate treaty followed; in June 1897 Ernest Noirot took over as administrator and set about ending slavery. The chiefs were kept on as figureheads until 1904, when France stripped their power outright. In 1905 even the loyal Alfa Yaya was arrested and exiled. The conquest was complete, and a way of governing that had outlasted its neighbors was gone.