The Igbo language[16] is part of the Niger-Congo language family. Its regional dialects are somewhat mutually intelligible amidst the larger "Igboid" cluster.[21] The Igbo homeland straddles the lower Niger River, east and south of the Edoid and Idomoid groups, and west of the Ibibioid (Cross River) cluster.

Before the period of British colonial rule in the 20th century, the Igbo were politically fragmented by the centralized chiefdoms of Nri, Aro Confederacy, Agbor and Onitsha.[22] Frederick Lugard introduced the Eze system of "warrant chiefs".[23] Unaffected by the Fulani War and the resulting spread of Islam in Nigeria in the 19th century, they became overwhelmingly Christian under colonization. In the wake of decolonisation, the Igbo developed a strong sense of ethnic identity.[24]

After ethnic tensions following the independence of Nigeria in 1960, the predominantly Igbo region seceded from Nigeria and attempted to establish a new independent country called Biafra, triggering the Nigerian Civil War (1967-1970).[25] Millions of Biafran civilians died from starvation after the Nigerian military formed a blockade around Biafra, an event that international media promoting humanitarian aid for Biafra alleged to be a genocide. Biafra was eventually defeated by Nigeria and reintegrated into the country. The Movement for the Actualization of the Sovereign State of Biafra and the Indigenous People of Biafra, two sectarian organizations formed after 1999, continue a non-violent struggle for an independent Igbo state.[26]