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The Nri Kingdom (oldest kingdom in Nigeria) in the Awka area was founded in about 900 AD in Northern Igboland. It was a center of spirituality, learning, and commerce. They were agents of peace and harmony whose influence stretched beyond Igboland and their neighbours. The Nri people's influence in neighboring lands was especially in Southern Igalaland and Benin kingdom. As great travelers, they were also business people involved in the long distant Tran Saharan trade. Since they were against slaves and slavery, their power took a downturn when the slave trade was at its peak. The Benin and Igala imperial slave raiding empires became the dominant influence in their relationship with Western and Northern Igbos.
Agbaja is an area located between Awka and Enugu in Northern Igboland. They are known for their iron work, pyramids, etc. I dont have enough information on them yet. Look at these unheard of pyramids the Agbaja of Igboland built in the videos and pictures provided...
The Aro Confederacy was a large slave oligarchy centered in Arochukwu in Eastern Igboland. They formed in the mid 17nth century as agents of Ibini Ukpabi and slave businessmen. Their influence covered Southeastern Nigeria, Southern Igalaland, Western Niger Delta (Urhobo and Isoko areas) through exploiting their oracle Ibini Ukpabi for slave trade, alliance with their related warlike neighbors (Ohafia, Abam, Edda, Ezza, and other Cross River communities), and other business oligarchies like Awka and other towns. Another advantage was their location between the Igbo, Efik, and Ibibio. The Aro Confederacy's power ended in the mid 1800s. The British officially ended the Aro Confederacy's economic power in the Anglo-Aro war in 1901-1902.
Onitsha is a town also located in Northern Igboland (west of Nri and Awka) and on the River Niger which formed in the 1500 by the Umu Eze Chima clan who were said to either be Benin immigrants, Igbos retreating from Bini conquest, or a Aro leader and his supporters. Either way the Onitsha kingdom like their Western Igbo neighbours who were said to have stoutly resisted the invading Binis but were highly influenced by the Benin empire's political organization. Onitsha kingdom became important during the slave trade and resisted Igala's lightining slave raids.