The 1840 Osogbo/Jalumi War

After the Fulanis outmanoeuvred gullible Afonja and captured and made Ilorin their territory, they attempted to conquer the old Oyo Empire in 1835/1836. But true to type as clever Alecs, the Oyos under Alaafin Atiba played smart and relocated the capital of the empire from Oyo - Ile to the present Oyo - Alaafin rather than cede Oyo empire to the invading aliens. Then they dared the Fulanis to pass through Ogbomoso before getting to them in their new location.
It was on good record that 70 x 200 = 14,000 Fulanis were buried alive at a spot known as Igba - Aláâdórin (meaning 200 x 70) by the then reigning Soun Ajagungbade 1, who was a ruthless warrior, highly versatile in the art and usage of African metaphysics.
The possibility that these bands of 200x70 aliens and invaders were on their way to the current Oyo location to capture and install an Emir like they did Ilorin, before they met their waterloo cannot be ruled out. Losing 14,000 soldiers in a single day was too much for the Fulanis, they stepped down their plan to invade new Oyo and ran to fight another day.
Soun defended Ogbomoso flanks where the army of the aliens would have marched to new Oyo location through Odo - Oba. 
In as much as they were still not satisfied with their victory in Ilorin; they wished to extend their rule deep into the heart of Yoruba land. And undeterred by their disgrace and defeat in in Ogbomoso, in 1840, they regrouped again and set to capture Osogbo, another Yoruba town. Maybe from there proceed to Ilesa to install an Emir there, then from there to Ekiti, Ondo and Akoko hinterlands. The Fulanis, under the command of Ali, a chieftain of Ilorin, laid siege on Osogbo.
When the king of Osogbo realized that the Ilorin Fulanis were too strong for the Osogbo army, still managed to stand his ground and not cave in.
The king of Osogbo therefore summoned the Ibadans for help and reinforcements. Ibadan immediately sent some auxiliaries to Osogbo under the command of Obele alias Mobitan, and Alade Abimpagun. As this forces could not stop the Ilorin Fulanis, another contingent was sent to Osogbo again under a more experienced leader.
Ilorin soldiers now consist of Fulanis and a mixed multitude of Yoruba indegenes that had been hoodwinked, brainwashed and blindfolded with religion by the Fulanis to think they are fighting on God's side against their own "pagan" people!
When Ibadan realized that the Ilorins now comprising of Fulanis and mixed mulititude Yoruba religious zaelots, were becoming more threatening to Yoruba land, they sent a large and stronger force under Balogun Oderinlo to crush the intruding forces and Jammas of Ilorin.
Initially when Oderinlo and his men arrived at the battlefield, they realized that things had gone worse than they thought.
They could not show their face in the open field for the fear of the Ilorin horses, and for about 20 days after their arrival at Osogbo, they could not fight outside the town thickets. Therefore they returned to the drawing board to chart out a better deadlier strategy against these aliens.
Other Yoruba warriors joined forces with their armies, with the nod and consent of Alaafin himself. Then began the mother of all battle was fought in a war called "Jalumi war" in between Okuku in present Osun - State and Offa in present Kwara State.
This is where the horses and chariots of Fulani invaders got drowned in a river nearby.
It was called Jalumi war because jalumi in Yoruba language means "jump inside river" The Fulanis got dexterity at riding horses but they can't swim. And the Yorubas true to type with their cunny craftiness hedged the flanks of the Fulanis and their Ilorin religious zealot cohorts close the river. As the army of Fulani invaders were being hit with both physical and metaphysical weapons, into the river they fell with their horses and drowned, since they can't swim! The ones among them that attempted to escape slided into the river got drowned both they and their horses.
Only few among them escaped back to Ilorin to tell their tale of woes to their Emir, that the battle is not really to the strong. To borrow a passage from Eccleasiates in The Bible.