“Metropolitan dissension, provincial disaffection and Muslim rebellion” is Robin Law’s succinct summation of the main features of Old Oyo’s demise. The precise manner of their interplay is less easy to determine. The coincidence in the third quarter of the 18th century of prolonged conflict between the Alaafin and the Basorun, head of the senior line of chiefs, with Oyo’s growing involvement in the coastal trade suggests that provincial authority (Esos, Ilaris and titled administrators)’s access to new resources seriously destabilized relations within the capital.
Alaafin Abiodun’s death in 1789 led to a recrudescence of quarrels between his successor Awole and his chiefs, disputes into which several provincial rulers and administrators were drawn. The most important of these was Afonja Laderin, ruler of Ilorin, who was also the Aare Ona Kakanfo or commander of the military levies from subordinate towns. When Awole was deposed, (c. 1796), Afonja made another bid to be chosen Alaafin and when this was also unsuccessful (being only related to the House of Oranmiyan through his mother), he seceded.

Over the next few years, Ilorin carved out an independent territory for itself from the Northeastern corner of the Kingdom, while at Oyo, the debilitating struggle between the Alaafin and his chiefs continued. In 1817, Afonja, though not a Muslim himself, decided to enhance his following by calling up the growing Muslim interest. He invited to Ilorin an influential Fulani Muslim cleric known to the Yoruba as Alimi, who soon proclaimed jihad against pagan Oyo which won the backing on Yoruba and non-Yoruba Muslims in the empire which in turn provoked a revolt amongst slaves on Northern (northern Yorubaland) origin.

Afonja’s war bands, known as the Jamaa, ranged further and deeper into the Oyo Kingdom, the young Ajayi Crowther being one of their victims. Around 1823, Afonja was killed in an insurrection of his Muslim allies and Alimi’s son Abdulsalami took charge of Ilorin, declaring his allegiance to the Sokoto Caliphate. By this time, Oyo’s eastern provinces has fallen away all together, and refugees were flooding to the forest regions South and East, beyond the borders of the old Kingdom.

Developments at the coast had equally far reaching effects, which by the 1820s combined with those in the North to redraw the regional map radically. From the 1790s, Lagos had begun to eclipse Oyo’s client kingdom, Port Novo as the chief outlet of the slave trade. This brought the Ijebu into greater prominence as a supplier and by the 1810s led to intensified slave raids in her hinterlands. When come Oyo traders were kidnapped at Apomu, a market town under Ife’s administration, Oyo demanded that their local ally, Owu take action: Apomu was invaded, sacked and Ife’s army defeated. Ife then made an alliance with the Ijebus, both armies laid siege on Owu-Ipole and took it in 1822.

The combined force of Ife, Ijebu and Oyo, after the sacking on Owu, turned their attention to the small Egba towns who were once subject to Oyo and annihilated nearly every one of them (1823 – 1824), many of those enslaved by these wars grew up to become CMS agents. The shattered Egba eventually regrouped on the Western edge of their territory, at a new settlement surrounded by large rocks; Abeokuta. The old Egba settlements; Ijaye and Ibadan for example were resettled by Oyo refugees. Meanwhile, Dahomey was eventually able to throw of Oyo suzerainty and began its own career of expansion into Yoruba speaking lands. For the rest of the century, the southwestern Yoruba where Oyo’s influence had lately been so strong, would be a bone of contention between Dahomey and Abeokuta.

Oyo itself lingered on for over a decade. The first eye witness account of it by Europeans in 1826 – 1830 described it as a “large, dull city,” tumbledown and semi deserted, with the people apathetic in the face of Fulani encroachments, yet the road up from Badagry through Egbado, the old conduit of Oyo’s coastal trade, was still secure and peaceful. Not for long: from 1831 – 1833, Ilorin, under its Fulani emir, reduced Oyo to tributary status and overran nearly all its provincial towns in the North and West.

A last attempt to throw off the Fulani failed, the Alaafin Oluewu was killed and Oyo’s remaining inhabitants fled South (c. 1836). A son of Alaafin Abiodun, named Atiba, who had once professed Islam at Ilorin, secured the support of Oyo’s remaining senior chiefs and warriors to be recognized as Alaafin and established himself in the South at a place called Ago-Oja., which eventually became the new Oyo.

Here, he and his successors recreated as much as they could the palatial pomp of the old capital. But in the face of the threat from Ilorin, practical measures were also needed. Astutely recognizing the new centers of power, Atiba conferred high Oyo titles on 2 principal warlords: Oluyole of Ibadan was made Basorun, and Kurunmi of Ijaye, Are Ona-Kakanfo. A working alliance was thus set up among the Oyos displaced to the South, which proved its worth when the Ilorins were defeated at Osogbo, decisively checking their Southwards advance (c. 1838). Ibadan was now revealed as the fulcrum of Yoruba society.