A Muslim Fulani, he began teaching in about 1775 among the Hausa and established the Emirates of Northern Nigeria (1804–08) after waging a jihad (holy war). He conceived the latter as a primary duty, not only against infidels, but against any departure, public or private, from the original and austere ideals of Islam. Under his rule as caliph, and that of his son, Muhammad Bello (died 1837), Muslim culture flourished in the Fulani empire.