The Sokoto Caliphate or Fulani Empire is an Islamic spiritual community in Northern Nigeria, led by the Sultan of Sokoto (currently Sa'adu Abubakar). It was founded during the Fulani War in 1809 by Usman dan Fodio. In the 1800s, it was one of the largest and most powerful empires in sub-Saharan Africa until British conquest in 1903. When the British took over the territory the political authority of the Caliphate was abolished and put under the Northern Nigeria Protectorate; however, the title of Sultan was retained and remains an important religious position for Muslims in the region to the current day.
Read more about Sokoto Caliphate: Sokoto Caliphate History (1804-1903), Decline and Fall, The Sultan of Sokoto During Colonialism and Independent Nigeria