Hausa history is one of immigration and conquest. The Hausa nation has evolved from the incorporation over hundreds of years of many different peoples who joined the original stock. They are united by a common language and adherence to a common religion, Islam. According to tradition, the Hausa people derive from the Hausa bakwai, the "true" seven states, of which Daura (named after its female founder) is considered the most senior. In the myth of origin, Bayajidda, the son of the king of Baghdad, arrived in Daura via Bornu. He killed the snake that occupied the well, impeding the townspeople's access to the water. As a reward, Bayajidda married the queen. Their son Bawo was the progenitor of six sons, thereby founding six states—Daura, Katsina, Zazzau (Zaria), Gobir, Kano, and Rano. Bayajidda's son by his first wife, Magira (a Kanuri woman), founded Biram, the seventh state.
In fact, it is not known when the movement of peoples actually occurred; neither has the migrants' place of origin been pinpointed. The seven Habe kingdoms were formed by a coalescence of strangers with local folk. The emergence of states in Hausaland was apparently associated with the establishment of capital cities as centers of power. They were different from earlier settlements in that they were cosmopolitan, fortified, and each the seat of a king who was recognized as the superior power throughout the surrounding area.
Before 1804, Habe kings ruled over Hausaland; following 1804, the Fulani took over, and by mid-century the Hausa were stratified into three tiers: the hereditary ruling Fulani, the appointive ruling class dominated by Fulani, and the Habe commoners.
Hausa relations with others are considerable, because of their extensive involvement with trade and Islam. There is considerable exchange with the Kanuri to the east, the nomadic Tuareg, and southern Nigerians (Igbo, Yoruba); in their diaspora settlements, other ethnic groups that share their cultural orientation, such as the Wangara, the Zabarama, the Adar, the Nupe, are often lumped together with them as "Hausa."