In 1964, the Organization of African Unity (OAU), the forerunner to the present-day African Union, declared at its Cairo summit that colonial borders would not be altered to reflect on-the-ground realities regarding ethnicity, language, and/or religion. With little debate, the OAU declared that the colonial boundaries of Africa, agreed to in far-away places like Berlin, Paris, London, and even the remote North Sea island of Heligoland, would serve as post-colonial international borders recognized by the United Nations and the tenets of international law. New states could only be carved out of old colonial entities if the post-colonial governments approved. Such approval would not come without a long and protracted armed fight.
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