02/01/2026
RISE OF THE OYO EMPIRE
The empire of Oyo was based around the city of Oyo Ile, situated south of the river Niger in the savanna zone near its convergence with the forest zone in what is today the northeastern corner of Oyo State.
It is unclear when exactly the town of Oyo Ile was founded, but archaeological testing indicates that the town was inhabited as early as the eighth century AD. Oyo Ile was a well-established urban center by the fifteenth century, when the neighboring Nupe sacked the city. The Oyo monarchy sought refuge among the Borgu, another neighboring people, to the west, where it reconstituted itself.
By the early sixteenth century, Oyo had moved its capital to Igboho, roughly forty miles west of Oyo Ile, and sometime in the late sixteenth century, under the reign of Ajiboyede, the Oyo defeated the Nupe and reclaimed Oyo Ile.
From about 1600, Oyo underwent rapid expansion into the forest zone to the south and southeast, becoming one of the largest empires in the Nigerian region. At its largest size in the eighteenth century, the Oyo empire stretched from the river Moshi in the north down the river Niger in the east to Ogudu, which was a Nupe settlement.
In the east, Oyo may have stretched as far as the river Osin in Igbomina territory, while, in the southeast, Oyo bordered on the lands of the Ekiti and the state of Ife. Oyo reached as far south as the present town of Oyo, while the river Opara marked the western boundary of the empire. In all, the area of the empire was somewhere in the range of 18,000 square miles. Although Oyo Ile stood in the savanna and cohabited with middle belt neighbors such as the Nupe and Borgu, Oyo was essentially a Yoruba state, although some political and cultural exchanges did occur between Oyo and its neighbors.
As was the case with most Yoruba states, the leader of Oyo, known as the alafin, traced his authority back to descendants of Oduduwa, the founder of the Yoruba people, who spread out from Ife. Oyo’s tradition claims that the city was founded by Oranmiyan, a son of Oduduwa. This link to Oduduwa and Ife was not the only foundation upon which the alafin’s authority rested, however. The alafin also claimed descent from Sango, an early King of Oyo later deified as the god of thunder, further mystifying the office of alafin and connecting it to the realm of the gods.
The office of alafin apparently had supreme authority, and only the alafin or one of his proxies could make policy decisions, order executions, and create and confer titles. Over time, the royal lineage also took more and more direct control over the functioning of the slave trade, one of Oyo’s most prosperous enterprises. Despite this supreme authority, however, the alafin did have several checks on his authority. The main political unit of Oyo was the lineage, and the alafin’s lineage was just one of many, although undoubtedly the most powerful. Each lineage had a head, and the head of each important lineage had a duty to perform for the state.
Lineage heads held political, religious, or military offices in the city or in the provinces of the empire and were responsible for the day-to-day administration of their purview. Local lineage heads often served as patrons for communities in the provinces of the empire. In return for tribute, these chiefs would lobby on behalf of their constituent communities for favors from the alafin. The most important lineage heads, aside from the alafin himself, held positions in the Oyo Mesi, a non-royal organization that served as the chief advisory body to the alafin.
The Oyo Mesi led the army of Oyo Ile, and its members served as the custodians of many religious centers for the city, among other duties. The Oyo Mesi also had the prerogative to approve of the royal lineage’s choice of a new alafin and could enact regime change by ordering disgraced or ineffective alafins to commit su***de. Such powers made it possible for the Oyo Mesi to exert significant, sometimes even disruptive, control over the office of alafin. The most famous example is the case of Gaha, who, as the basorun, or leader, of the Oyo Mesi from 1754 to 1774, secured the su***des of two alafins, Labisi and Awonbioju.
Gaha then forced Awonbioju’s successor, Agboluaje, to accede to Gaha’s authority, over which issue Agboluaje eventually committed su***de. It is speculated that Gaha may also have been responsible for the death of Agboluaje’s successor, Majeogbe, supposedly through magic or poisoning. Gaha was eventually overthrown by Alafin Abiodun, who called upon aid from the provinces of Oyo to end Gaha’s tyrannical rule. That the office of alafin did not crumble under the instability created by Basorun Gaha and the Oyo Mesi is a testament to the organization of the alafin’s palace administration, which rested heavily on slaves with positions of high authority and responsibility.
It is clear that, from the reconquest of Oyo Ile in the late sixteenth century, slaves had performed integral duties within the palace administration, not only in the everyday affairs of running the palace but also in ruling the city of Oyo Ile and the provinces of the Oyo empire.
Three eu**chs, known as the ona iwefa (eu**ch of the middle), otun iwefa (eu**ch of the right), and osi iwefa (eu**ch of the left), were the most senior titled slaves and were the highest authority next to the alafin himself in judicial, religious, and administrative matters respectively. The ona iwefa stood as proxy for the alafin in handing down legal rulings, while the otun iwefa was in charge of the cult of Sango, through which the alafin’s office was mystified.
The osi iwefa collected revenues and served as the alafin’s proxy in dealings with lineage heads such as the members of the Oyo Mesi. Beneath these three titled eu**chs was a larger class of palace slaves known as the ilari, meaning ‘‘scar-heads,’’ a reference to the incisions made in their heads into which magical substances were rubbed, initiating them into their new rank. These slaves numbered several hundred if not thousands, and were under the purview of the osi iwefa. Ilari served the alafin as tax collectors, messengers, and bodyguards.
To enable the alafin to keep an eye on events in the provinces of the empire, a group of slaves known as the ajele or asoju oba (eyes of the king) were placed throughout the Oyo empire and reported directly to the alafin on matters affecting their assigned province. The reliance on slaves for the overseeing of the alafin’s affairs stabilized royal authority in two ways. First, since the duties of slaves were so diffused and carried such importance, royal authority could be maintained even if the alafin himself was ineffective or was suffering through periods of instability, as in the period of Basorun Gaha.
Second, since slaves had no lineage of their own and therefore no power to gain, other than that which could be conferred upon them by the alafin, their dependent status made them particularly stable and trustworthy underlings. In this way, the Oyo empire managed to thrive on a series of checks and balances between royal and non-royal lineages, propped up by a fairly dense bureaucracy based on slave labor. Slaves also served much the same functions in Oyo as they did in other regions of the greater Nigerian area during the 1500–1800 period. Slaves performed agricultural work, performed domestic duties, trained as artisans, and served in the military.
With slaves such an important aspect of the politics and economy of Oyo, it is no surprise that the trade in slaves was also a central element in the rise of Oyo. Oyo traded slaves captured in war, and to a smaller extent convicted criminals, as well as European goods attained through southern trade, to Hausa states in exchange for Hausa slaves and, perhaps most importantly, the horses upon which Oyo built the cavalry it used to dominate the region militarily. Oyo also traded slaves south to the coast after 1650 in exchange for European luxury goods, cowry shells, which were the standard currency of Oyo, and, during the eighteenth century, a limited supply of fi****ms.
Oyo’s involvement in the slave trade was not restricted to the slaves acquired in Oyo’s own military campaigns. Oyo’s strategic position between the southern forest zone and the Hausa states put Oyo in a prime position to capitalize on the flow of goods between the two regions. Oyo thus served as a middleman, imposing heavy financial burdens on traders wishing to pass through Oyo territory to sell their wares on the other side. Hausa merchants wishing to move south and forest zone traders wishing to trade north found that they were forced to pay heavy dues when passing through Oyo territory.
Ultimately, most merchants found it in their own economic interest simply to sell their wares in Oyo, rather than pay the dues necessary to pass through Oyo. Oyo merchants could then re-export these goods in whatever direction they chose, at inflated prices. Government traders within Oyo did not pay the fees to pass through Oyo and as such they were at a competitive advantage over other traders in the region. This was particularly true of the trade in slaves, which the royal lineage of Oyo itself dominated in the eighteenth century.