pottery dated at around 2500 bc showing similarities with later igbo work was found at nsukka in the 1970s, along with pottery and tools at nearby ibagwa; the traditions of the umueri clan have as their source the anambra valley. in the 1970s the owerri, okigwe, orlu, awgu, udi and awka divisions were determined to constitute "an igbo heartland" from the linguistic and cultural evidence.