HISTORY OF THE ISU
Winding it's way through the highlands at Isu, the Njaba River makes it's way in a snake-like meander through Amucha, Ekwe, Okwudor, Awo-Omama, Izombe and ultimately empties into the Oguta lake... the silty river has it's origin in the IsuNjaba a town in Isu local government, it's an abundant source of native chalk and the Njaba River basin has rich oil deposits, with the oil well at Izombe currently one of the largest in Imo State but that of Awo Omama is currently sealed as reserve.
The legend of origin of the native peoples has it that Chukwu(God) created the first man out of the Njaba River and that he and his son Isu and wife Lolo populated all the villages and towns through their children.
WHO ARE THE ISU?
The Isu or Isuama as they are also known are an insular group who inhabit the central area of Igbo between southern Anambra State and Northern Imo State(Orlu) they could be divided into Western Isu (Orsu), Isuama proper and Eastern Isuama(Mbano)
Both G.I jones, Afigbo and Elizabeth Isichei agree that the core area of the evolution of Igbo groups are the Nri-Awka-Orlu axis and the Okigwe-Udi ridge. Afigbo goes on to explain that they disperesed in waves of 9 groups.
Isu just happens to be one of such groups, an insular group that remigrated amd stayed back in the Igbo heartland.. under current political dispensation, it would mean the current Orlu, Orsu, Oru East, Oru West, Ideato North and South, Nkwerre, Nwangele, Nnewi South, parts of Ihiala and parts of Aguata. These are the core areas of Isu settlements. G.I Jones believes the Isu Njaba to be the source of the Isu civilization from where they spread out to the other areas. Thus Isu njaba maintains the sacred priesthood of the Njaba deity to this day.
Part of what is Isu homeland today included the whole lot of Anambra South, however a southward push of Eri people in a series of migration and population explosion forced a chain reaction such that many of the Isu moved South. Leading the dispersal of Isu to several areas where they formed splinter communities.
The Southward push of the Eri groups they settled amongst aboriginal Isu settlements with which they formed conderacies that became known as Orsu (a mingling or mixing of peoples) the Orsu in culture and language are still Isu but with heavy Nri cultural influneces, they include Oru East, some towns in Ihiala LGA, Nnewi South, Orsu and parts of Orlu.
This is attested by the fact that there are still many settlements in Southern Anambra with the suffix of Isu or Orsu.
The Eastward expansion of the Isu came as a result of population pressure, it put the Isu into conflict or apposition with the native Agbaja people.. one such such example is the Isu expansion into what is known as Mbano today led by one Elele Nwogwugwu the father of Ehime clan....they surplanted and assimilated the native Agbaja/Okigwe peoples... also the Isu expansion into Etiti and what is known as Onuimo today where they established Okwelle and Umuna amongst others.
There were also further Isu settlements in what is Mbaitoli today, Ikeduru clan, Ohuhu(Mbaise) and as far as Ezza, Uturu,and Bende axis where we have Isuikwuato today(who are aboriginally known as Otanzu)
In the West some certain developments such as war with Aboh led Oru people(riverine Igbo) from the banks of the Niger to migrate inland..to the result that many settled in Isu...some of them settled in search of fishing grounds along the Njaba River...the Ndoki was part of these Oru movement, not finding subsequent fishing grounds they continued all the way to the Imo River and the finally settled where they live now in Abia State while some of them continued to Bonny island.
Some of the Oru from Oguta axis also settled in Awo Omama, Amiri, Uli, a lot of them settled in what we know as Orodo today.
The hallmark of Oru mingling with Isu is that they introduced the Owu cult into Isu, the mmanwu had been the major masquerade of the Isu but the Oru introduced Owu which has since taken prominence, owu amongst the Oru had nine levels at the highest of which was Okoroshi, these institutions were borrowed in different degrees by the Isu. Owu season is celebrated every year in a series of events that culminates in the New Yam festival.
Another interesting feature of Isu culture is the sacredness of the python...it is a remarkable feature of every Isu community that the dwarf python is their mother or a messenger of the River e.g Eke Njaba, it is a totem that is repleted in every Isu community.
Isu dialect has some unique features such as they say Okwara instead of Okpara, obi instead of Obu or Obiri. however Isuama is the main central Igbo dialect on which much lexicon of central Igbo was built
Isuama shares more deities with Nri than it does with Southern Igbo, they use a four day market system and Amadioha was not popular there.
Concerning their relationship with Nri, i must mention one thing,
Nnewi was one of the epicenter of Isu civilization and culture hece they mention Isu in their oral tradition all be it in a metaphoric story However, with the downward shift of Eri people and the establishment of Nri hegemony the Nri who were advanced in priestcraft established a royal priesthood. Nnewi used to be known as Isu Agbaja. Another factor which led to the dispersal of the Isu came into the picture, it was the Aro, the Aro were in competition with the Nri over priestly supremacy. some faction within Isu Agbaja (Nnewi) with the local guild of blacksmiths connived with the Aro and usurped the priest-kingship of the Nri lineage and replaced it with a political monarchy(Igwe) which is still in power today, a nephew of the major Isu priest was made king, i will not go into full details of Nnewi history here but know that eventually tsome Isu agbaja left and the guild of blacksmiths were expelled with their leader (okwaraeshi) and they went and settled over lands given them by Amaigbo today, they are Nkwerre today.
It was also during this military takeover by the Isu with Aro help that part of their group led by Umejei(known in nnewi as Omeji) left to found Igbuzor.
The population dispersal of the Isu was partlyas a result of the area which they lived in...the soil was barren and infertile and so it did not yield a lot of crops and could not sustain a large population so the Isu did not excel in farming, they largeky engaged in trade and servitude..they travelled largely south into Upland Rivers territories where they offered services as laborers, such that they were hired farmers for the people with vast tracts of arable farmland, they became known as Isu aka mma or Isumma for short later corrupted to Isoma which Owerri people, Ohaji, Egbema, Agwa, Etche and Ikwerre now call isu people in general or anybody from the hinterland.
Also being people did not live in nucleated civitas or proper towns but rather settled in disperesed forested formation the Owerri and the Aro looked down on the Isu as nde ime ohia(bush people)
The Isu had a value system of wealth...they did not have elaborate title taking institutions but some of them adopted ozo institutions from Nri especially Orsu communities.
while within Owerri, Mbaise and Ikeduru the Duru title was strictly priestly, within Isu(Orlu area) it was based on wealth..thus it was a society that made measure if men based on wealth.