The Islamic religion was introduced into the Hausa land (precisely Kano) during the reign of Sarki Yaji in the middle of the 15th Century AD.
But before then, it was assumed that it had been in existence in Borno state because the Hausa words for reading and writing introduced by Muslims were of Kanuri origin.
Hence, it became the state religion in Kano under the leadership of Mohammed Kumfa, who built mosques and introduced Islamic laws.
Moreover, it extended to Zaria during the reign of Mohammad Rabbo and to Katsina during the reign of Mohammad Korau. Mohammad Korau was converted by Al Maghili of Egypt.
Meanwhile, before the advent of the foreign religion (Islam), the Hausa people were pagans and idol worshippers.
Again, Islam did not reach other cities in Hausa until the Jihad of Dan Fodio in the early 19th century.
Thus, until then, most Hausa rulers were practicing and encouraging Syncretism.