Aro History starts from Ibibio migration to the present Arochukwu area.
Before Igbo arrival in the Aro territory, a Semi-Bantu group of the Ibibio arrived around 300 AD from the Benue valley. They mainly inhabited the area now known as Southeastern Nigeria. Prominent settlements were Ibom and Obong Okon Ita. These hunters and farmers perhaps lived peacefully until foreign settlers invaded.
The Igbo migration led by Eze Agwu clan from Abiriba among the Ibibio in the Aro territory started around the 17th century. Tensions escalated between the Eze Agwu group led by Agwu Inobia and Obong Okon Ita kingdom led by Akpan Okon resulting in the Aro-Ibibio Wars. Neither group had a victorious position in the war. Eze Agwu asked Priest Nnachi of the Edda clan near Afikpo for help. The alliance also supported prince Kakpokpo Okon's coup against his brother Akpan Okon. The war escalated and Nnachi called on Eastern Cross River allies for assistance.
Osim and Akuma Nnubi were Akpa merchant princes from the Akamkpa area. They led Akpa forces into the Aro territory to assist their Igbo allies to victory. However, this came at the cost of Osim losing his life at the start of the 18th century. With the Akpas and Igbos being victorious, the Arochukwu kingdom was founded with Akuma as its first king or EzeAro. After Akuma died, the Igbo took over the throne starting with Nnachi's son Oke Nnachi in 1720. Many changes occurred as Arochukwu expanded into 19 city-states due to the increasing population and Aro colonies were forming throughout the area now known as Southern Nigeria.