On th frontier of empire: Understanding the enclosed walls in Northern Yoruba, Nigeria

The enclosure walls found among small-scale societies of Igbomina in northern Yoruba shared similar characteristics with some well-known walls of large political centers in various parts of tropical Africa, particularly Nigeria. The study of settlement walls of Igbomina provides an understanding of the nature of the Yoruba frontier region in the north. By virtue of its location on the border with the Nupe to the north, Igbomina became a competing zone between rival core polities, the Old Oyo and the Nupe, and later, Fulani and Ibadan states. It therefore seems that the construction of enclosure walls was to counter aggressions on the frontier and protect local communities from invaders. However, the functions of enclosure walls in Igbomina may have fluctuated from defensive to sociopolitical. The rise and expansion of Old Oyo Empire into Igbomina from the 16th century and the formation of relations with the local elites brought greater sociopolitical changes to the area, evident in settlement aggregation, large site size, and ceramic changes. Thus, enclosure walls may have been a good indicator of the power of the local rulers and a symbol of cohesive social organization within the settlements. Ethnohistorical sources, archaeological survey, and excavation form the core of this examination of settlement walls on the northern frontier of Yoruba.