Hausa Kingdoms
By 1808 Uthman had defeated the rulers of Gobir, Kano, Katsina, and other Hausa Kingdoms. After only a few years of the Fulani War, Dan Fodio found himself in command of the hausa state, the Fulani Empire. His son Muhammed Bello and his brother Abdullahi carried on the jihad and took care of the administration. Dan Fodio worked to establish an efficient government grounded in Islamic law. After 1811, Usman retired and continued writing about the righteous conduct of the Muslim religion. After his death in 1817, his son, Muhammed Bello, succeeded his as "amir al-mu’minin" and became the ruler of the Sokoto Caliphate, which was the biggest state south of the Sahara at that time. Usman’s brother Abdullahi was given the title Emir of Gwandu and was placed in charge of the Western Emirates, Nupe. Thus all Hausa states, parts of Nupe and Fulani outposts in Bauchi and Adamawa were all ruled by a single politico-religious system. By 1830 the jihad had engulfed most of what are now northern Nigeria and the northern Cameroons. From the time of Usman dan Fodio to the British conquest at the beginning of the twentieth century there were twelve caliphs.