The people who occupy the territory known as Abiriba descended from the Igbo and Efik people of Calabar. They migrated from the upper Cross River area centuries ago led by a Nnachi Oken, from whom the title "Enachioken" ("The Monarch") originates. Initially, they occupied a smaller territory which expanded when the Abiriba people routed the surrounding Nkporo people and took over their lands. The Abiriba people were war-like and quickly established themselves in the area.
The origin of the Abiriba people is not as speculative as the origin of other Igbos of southeastern Nigeria. Historical evidence supports the fact that Abiriba people have common ancestor with the Yakor tribe of Ekoi of cross river basin and the people of Arochukwu. At Ekoi, constant disputes between the seven families under Ukpaghiri prompted the clan to move to Ena and finally to Akpa.
The settlement at Akpa was difficult for many years due to hostilities with neighbors. After the death of Ukpaghiri, Mbiriba and his group moved to Usukpam and stayed there for many years but were never at peace with the neighbors. Mbiriba decided to move to Udara-ebuo whereas Otusi led the other branch of the family down stream and eventually founded Arochukwu. The term Nwajim is often used between Abiriba and Arochukwu people because of our common lineage. Mbiriba who had advanced in age, moved his group once more and settled at Udara-ebuo.
Nature was inhospitable to the inhabitants at Udara-ebuo. There was no water and the place was overrun by monkeys. Oral history has it that monkeys used to visit homes to look for food, and the people became sick living on monkey meat only. Mbiriba died at Udara-ebuo and left his son Ifa Mbiriba in charge.
Ifa Mbiriba finally moved to Uruanta and Agboha and settled there. The new settlement was very fertile and had a natural fortress. Thus, the name ABIRIBA was derived from the name Mbiriba or nickname “Ebiri-Aba”.
Oko Ogo opened Ndi Okogo which is currently where the Chief's Palace "The Agboezi" is situated. Nwagu Ifa founded Okagwe and later Agboji. Ngwu founded Ihungwu. Chukwu Oke founded Amogudu. The name Amaeke was derived from the market day Eke. The Capital of Abiriba is Ameke and the paramount Chief for the whole Abiriba uses the title Enachi-oken.
Incessant conflicts and border skirmishes between the Item and Amogudu led to the creation of a standing army in form of the age-grade system. Historical artifacts exist to support the consensus that the age-grade system started at Amogudu.
Nwagu Ifa, Ngwu, Oko Ogo and Chukwu Oke used the age-grade as a standing army to protect the Abiriba from hostile neighbors.