BASORUN GAHA, THE WICKED PRIME MINISTER
The Oyo Empire was monarchial and ruled by an Alaafin (King). However, an administrative and governing body, made up of chiefs (Oyo Mesi), served to maintain a balance in power. They were headed by a prime minister called Basorun and could request the king's suicide by sending him a calabash of parrot's eggs.
This Basorun Gaha was remarkable because he successfully enthroned 4 Kings, deposed 4 and was murdered by the 5th. Basorun (Prime Minister) Gaha, was a brave and powerful man who was respected and feared by the people of Oyo-Ile for his potent charms and supernatural strength. It was said that Gaa had the powers to transform into any animal he wished. Gaa was feared to the extent that he became more authoritative than the Alaafin who made him the Bashorun. It was also said that Basorun Gaa was most times controlled by his ‘juju’ powers which often made him misuse it.
GAHA'S ROYAL VICTIMS
Crown Prince Labisi- He didn't get the opportunity to even enter the palace. Gaha had his main supporters and friends, executed, forcing that prince to commit suicide.
King Awonbioju- Succeeded Labisi but lasted a mere 130 days because he refused to postrate before Gaha.
King Agboluaje- Succeeded Awonbioju and was a man of peace. He committed suicide because Gaha insisted that the Elewi of Ewi, a good friend of Agboluaje, was competing with the king in a fashion face off.
King Majeogbe- Agboluaje's brother who succeeded him. His problems began when his son was heard to be quarelling loudly in Gaha's part of town. Feeling that the prince was too lowly for his attention, he set his crosshairs on the father, the king.
King Abiodun- Abiodun wasn't about to suffer the same fate as his predecessors but his daughter Agbonyin was murdered by Gaha. To take down Gaha who had many powerful friends and connections, he lied to Gaha about being ill, disguised himself as a commoner and went to rally for external help from the Onikoyi and the Are-Ona-Kakanfo, Oyabi from Ajaseland, on how to send Gaha to the grave.
On the appointed day, troops overwhelmed Gaha, murdered his children including his pregnant wives and captured him alive.
Though he begged for mercy, he was burned alive, atop the remains of his homestead to make he did not reincarnate.
It must be noted that the death of the all-powerful Basorun Gaha affected the Old Oyo Empire in some ways. Firstly, it decreased the military and political strength of the Empire; this was due to the destabilization of the Oyomesi after Gaha’s death; the Oyomesi were supposed to act as a check to the Alaafin but instead became his puppet, and left him with absolute authority to rule the Empire.
Secondly, the political unrest the old Oyo Empire witnessed after Gaha’s death made some kingdoms under her auspices (like Dahomey) declare their independence. All these were undoubtedly among the factors that led to the subsequent fall of the old Oyo Empire in 1836/1837. 
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