It has been observed for a long time that the states of the Eastern Niger Delta responded in recognizable ways to the introduction of European overseas trade in slaves and palm-oil from the sixteenth through the nineteenth century. It is suggested here that by the time of European advent these states were already in the process of profound changes in response to other internal situations.
First, migration from the fresh water Central Delta to the salt-water Eastern Delta (possibly before A.D. 1000) dictated changes. A change from a farming to a fishing economy led to changes in the social and political system.
Second, the inability of the fishing economy to satisfy all the basic needs of these communities led to the growth of long distance trade to the hinterland and to other parts of the Niger Delta. This trade set in motion other structural changes which were accelerated by the European overseas trade.
Thus were the institutions of the farming village, based largely on age and the simple lineage, developed into the kingship (before about 1400) and House system (before about 1600) of the states of the Eastern Niger Delta, described variously as city-states and trading states.