In an attempt to extend the frontiers of Yoruba archaeology, between 1992 and 1994 I undertook an archaeological survey of northeast Osun State, Nigeria (see figure 3.1) with an emphasis on Ila-Orangun, Oke-Ila, Oyan, Asi, and Iresi, with a view to making the area known archaeologically. Hitherto, the area had been left unexplored by archaeologists. Most work done in southwestern Nigeria has concentrated on Ile-Ife, Benin, Old Oyo, and Owo, with their art works in bronze, terracotta, and wood. In Yorubaland, there are areas other than Ife, Old Oyo, and Owo that are prominent and vital to its history and archaeology. It is this notion that prompted me to start an archaeological exploration in northeast Osun State.

Previous archaeological work in this area is scarce. The only related investigation is that of P. A. Allison, who observed and photographed a head from Ikirun that was similar to an Ife head. My decision to work in northeast Osun was also informed by the desire to locate potsherd pavements in other Yoruba towns besides Ile-Ife, where the well-known Luwo-type potsherd pavements are found. These pavements cover almost the entire town of Ile-Ife. They are made primarily of potsherd laid on edge and either in a herring-bone design or in a straight row. The tradition is credited to Luwo, the only known female ruler in Ile-Ife.

The northeast part of Osun State under investigation comprises the notable ancient and historical towns of Igbajo, Ikirun, Iragbiji, Iresi, and Ajaba, the last-named being a town that links the southern and northern parts of Yorubaland. Between 1992 and 1994, I carried out a survey of parts of this study area with visits to Oyan, Asi, Asaba, Ila-Orangun, Oke-Ila, and Iresi, among other places.