Onitsha Mmili was known as Ado N’Idu by migrants who departed from the vicinity of the Kingdom of Benin near the far western portion of Igboland, after a violent dispute with the Oba of Benin that can be tentatively dated to the early 1500s. These migrants traveled eastward through what is now Western Igboland and various towns also called “Onitsha”, for example Onicha-Ugbo .
History of the Onitsha indigenes, “farmland-Onitsha”. Folklore has it that, Onitsha was founded by one of the sons of Chima, the founder of Issele-Uku kingdom in western Igboland. Chima, a prince who emigrated, settled and founded what is now known as Issele-Uku in Aniocha North Local Government Area. The eldest son of Chima eventually emigrated across the Niger River to establish the Onitsha community.
After their arrival on the east bank the community gradually became a unitary kingdom, evolving from a loosely organized group of “royal” villages to encompass “non-royal” villages comprising Igala settlers, and the native Igbos to form a more centralized entity. Eze Aroli was apparently the first genuinely powerful Obi of Onitsha, the ruler of the city.