Which Hausa states became major powers in northern Nigeria?

In the history of northern Nigeria, the Hausa states were a group of neighboring polities that, while lacking a central authority, included several that rose to prominence as major powers. Among the seven "true" Hausa states, or Hausa Bakwai, the following became particularly significant:12

• Kano: Historically one of the most powerful, Kano became a major commercial hub in West Africa by the 1820s, renowned for its leather and cotton goods.3
• Katsina: A principal rival to Kano in the trans-Saharan trade, Katsina eventually eclipsed Kano as a commercial center during the 17th century.3
• Zaria (Zazzau): A major state that exerted influence over its neighbors, including Kano, during the 16th century.3
• Gobir: Known as a significant state in the region, it was a central site of activity during the lead-up to the 19th-century Sokoto jihad.42

These states were eventually organized into emirates following the Fulani jihad in the early 19th century.1