The modern Esan nation is believed to have been organized during the 15th century, when citizens, mostly nobles and princes, left the neighbouring Benin Empire for the northeast; there they formed communities and kingdoms called among the aboriginal peoples whom they met there. There are on the whole 35 established kingdoms in Esanland, including Amahor, Ebelle, Egoro, Ewohimi, Ekekhenlen, Ekpoma, Ekpon, Emu, Ewu, Ewatto, Ewossa, Idoa, Ifeku, Igueben, Ilushi, Inyelen, Irrua, Ogwa, Ohordua, Okalo, Okhuesan, Onogholo, Opoji, Oria, Orowa, Uromi, Udo, Ugbegun, Ugboha, Ubiaja, Urhohi, Ugun, Ujiogba, Ukhun, and Uzea.