The Sahelian kingdoms were a series of medieval empires centred on the Sahel, the area of grasslands south of the Sahara.
The first major state to rise in this region was the Ghana Empire (Wagadu). The name Ghana, often used by historians, was the regnal title given to the ruler of the Wagadu empire. Centered in what is today Senegal and Mauritania, it was the first to benefit from the introduction of gold mining. Ghana dominated the region between about 750 and 1078. Smaller states in the region at this time included Takrur to the west, the Malinke kingdom of Mali to the south, and the Songhai Empire centred on Gao to the east.
When Ghana collapsed in the face of invasion from the Almoravids, a series of brief kingdoms followed, notably that of the Sosso (Susu); after 1235, the Mali Empire rose to dominate the region. Located on the Niger River to the west of Ghana in what is today Niger and Mali, it reached its peak in the 1350s, but had lost control of a number of vassal states by 1400.
The most powerful of these states was the Songhai Empire, which expanded rapidly beginning with king Sonni Ali in the 1460s. By 1500, it had risen to stretch from Cameroon to the Maghreb, the largest state in African history. It too was quite short-lived and collapsed in 1591 as a result of Moroccanmusketry.
Far to the east, on Lake Chad, the state of Kanem-Bornu, founded as Kanem in the 9th century, now rose to greater preeminence in the central Sahel region. To their west, the loosely united Hausa city-states became dominant. These two states coexisted uneasily, but were quite stable.
In 1810, the Sokoto Caliphate rose and conquered the Hausa, creating a more centralized state. It and Kanem-Bornu would continue to exist until the arrival of Europeans, when both states would fall and the region would be divided between France and Great Britain.
The West African empires of this period peaked in power in the late 18th century, paralleling the peak of the Atlantic slave trade. These empires implemented a culture of permanent warfare in order to generate the required numbers of captives required to satisfy the demand for slaves by the European colonies. With the gradual abolition of slavery in the European colonial empires during the 19th century, slave trade again became less lucrative and the West African empires entered a period of decline, and mostly collapsed by the end of the 19th century.
The Kingdom of Dagbon was founded by the Red Hunter Tohazee circa 11th Century. The Kingdom is one of the largest and oldest in modern Ghana.
The Kingdom of Nri was unusual in the history of world government in that its leader exercised no military power over his subjects. The kingdom existed as a sphere of religious and political influence over much of Igboland, and was administered by a priest-king called the eze Nri. The eze Nri managed trade and diplomacy on behalf of the Igbo people, and was the possessor of divine authority in religious matters.
The Oyo Empire (1400–1895) was a West African empire of what is today western Nigeria. The empire was established by the Yoruba in the 15th century and grew to become one of the largest West African states. It rose to prominence through wealth gained from trade and its possession of a powerful cavalry. The Oyo Empire was the most politically important state in the region from the mid-17th to the late 18th century, holding sway not only over other Yoruba states, but also over the Fon kingdom of Dahomey (located in the state now known as the Republic of Benin).
Benin Empire (1240–1897), a pre-colonial African empire of modern Nigeria. The empire once stretched to present day Ghana ruled by sky kings ( OGISO ) in the first dynasty and by OBAS in the second dynasty. It was the first kingdom to come in contact with the Europeans.
Bonoman (11th century–19th century), earliest known Akan state. Gold trading and Kola nut trading with Northern Neighbors brought wealth and prosperity to Akan creators of this state. Culture influenced much of modern Akan culture.
Gbokpoe Dynasty was founded in 1700. This dynasty ruled Djanglanmey, Grand-popo. In the region this clan was the famous slave trader.
The Kingdom of Wémè was founded during the height of the slave trade in the late 17th century. Nowadays it is centred in modern-day Benin, ruled by its own traditional legitimate monarch in the Ouémé Valley.
Ashanti Empire (1701–1894), a pre-colonial Akan West African state of what is now the Ashanti Region in Ghana. The empire stretched from central Ghana to present day Togo and Côte d'Ivoire, bordered by the Dagomba kingdom to the north and Dahomey to the east. Today, the Ashanti monarchy continues as one of the constitutionally protected, sub-national traditional states within the Republic of Ghana.
Various states by Akan people (11th century–19th century)
Bamana Empire (1712–1896), based at Ségou, now in Mali. It was ruled by the Kulubali or Coulibaly dynasty established c. 1640 by Fa Sine also known as Biton-si-u. The empire existed as a centralized state from 1712 to the 1861 invasion of Toucouleur conqueror El Hadj Umar Tall.
Sokoto Caliphate (1804–1903), an Islamic empire in Nigeria, led by the Sultan of Sokoto, Sa'adu Abubakar. Founded during the Fulani Jihad in the early 19th century, it was one of the most powerful empires in sub-Saharan Africa prior to European conquest and colonization. The caliphate remained extant through the colonial period and afterwards, though with reduced power.
Akwa AkpaDuke Town, originally known as Atakpa is an Efik city-state that flourished in the 19th century in what is now southern Nigeria. The City State extended from now Calabar to Bakassi in the east and Oron to the west.
Ife Empire (1200 - 1420) The Ife Empire was the first empire in Yoruba history. It was founded in what is now southwestern Nigeria and eastern Benin today. The Ife Empire lasted from 1200 to 1420. Its capital city, Ilé-Ife, was one of the largest urban centers, the biggest emporium, and the wealthiest polity south of the Niger River during the mid-14th-century.
The Kongo Kingdom (1400–1888) was a quasi-imperial state as is evident by the number of people and kingdoms that paid it tribute. If not for the large amount of text written by the EssiKongo that repeatedly called themselves a kingdom, they would be listed as the "Kongo Empire".
Vansina (1962) discusses the classification of Sub-Saharan African kingdoms, mostly of Central, South and East Africa, with some additional data on West African (Sahelian) kingdoms distinguishing five types, by decreasing centralization of power:
Despotic kingdoms: Kingdoms where the king controls the internal and external affairs directly. Examples are Ruanda, Nkore, Soga and Kongo in the 16th century
Regal kingdoms: Kingdoms where the king controls the external affairs directly, and the internal affairs via a system of overseers. The king and his chiefs belong to the same clans or lineages.
Incorporative kingdoms: Kingdoms where the king controls only the external affairs with no permanent administrative links between him and the chiefs of the provinces. The hereditary chiefdoms of the provinces were left undisturbed after conquest. Examples are the Bamileke, Lunda, Luba, Lozi.
Aristocratic kingdoms: The only link between central authority and the provinces is payment of tribute. These kingdoms are morphologically intermediate between regal kingdoms and federations. This type is rather common in Africa, examples including the Kongo of the 17th century, the Cazembe, Luapula, Kuba, Ngonde, Mlanje, Ha, Zinza and Chagga states of the 18th century
Federations: Kingdoms (such as the Ashanti Union) where the external affairs are regulated by a council of elders headed by the king, who is simply primus inter pares.
Hunwick, John O. (2003). Timbuktu and the Songhay Empire: Al-Saʻdī's Taʼrīkh Al-sūdān Down to 1613 and Other Contemporary Documents. Leiden: Brill Academic Publishers. pp. 488 Pages. ISBN90-04-12822-0.
Vansina, J. "A Comparison of African Kingdoms", Africa: Journal of the International African Institute (1962), pp. 324–335.
Turchin, Peter and Jonathan M. Adams and Thomas D. Hall: "East-West Orientation of Historical Empires and Modern States", Journal of World-Systems Research, Vol. XII, No. II, 2006