The survivors of the slave-raid had gathered under the uncertain shade of a clump of trees rising from the rough, red earth: “All the huts were burnt down,” the French military officer Lieutenant Fauré would report to his superiors, “Every gourd, jar and piece of pottery was broken.” Locusts and drought, Lieutenant Fauré recorded, had raged through the lands of the ethnic-Sara people through the summer of 1902. Then, as the weather turned to spring, a new plague emerged: Ethnic-Fulbé raiding groups set out from the Emirate of Bornu, ripping apart the villages of the Lake Chad basin for ivory, gold and slaves.

From his throne in Bornu, the warlord Rabih az-Zubayr bin Fadlallah had proclaimed slave-raiding a religious obligation, a jihad against the pagan tribes of the Lake Chad basin. French soldiers responded by sticking Rabih’s severed head on a pike in 1900, and then packed his skull off for display at the Musée de l’Homme anthropological museum in Paris.Two years later, though, hundreds of small children and women were still being captured in raids. Large numbers died of thirst and starvation, French officials reported. Fauré explained how his troops survived: “Fortunately there were a number of hippopotami in the Logone, and these served as food.”