This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Usman dan Fodio, a Fulani Islamic scholar, spent two decades teaching and writing against practices he judged un-Islamic among the rulers of the Hausa states of what is now northern Nigeria, including rulers who professed Islam but, in his judgment, mixed it with pre-Islamic custom and taxed their subjects beyond what the law allowed. In 1804 Yunfa, the king of Gobir and once dan Fodio's own student, moved against him, forcing his hijra to Gudu, where he was proclaimed commander of the faithful and raised the banner of jihad.
Early fighting went badly for his forces, most severely at the Battle of Tsuntua in December 1804, but successful campaigns against Kebbi in 1805 and against Katsina, Daura and Kano by 1807 broke Hausa resistance state by state, and Gobir itself fell in 1808 with Yunfa killed in the fighting. The conquered territory became the Sokoto Caliphate, administered under Islamic law with dan Fodio as its first caliph until his death in 1817, and it endured as one of the largest and most durable states in nineteenth century West Africa until the British conquest of 1903.