According to Henry Louis Gates, “about 24% of the ancestors of the African-American people” are descended from slaves brought from West Central Africa (Angola and Congo). From Angola, 2.8 million slaves were exported from Luanda and another 800,000 were exported from Benguela. 1/4th of all African slaves exported to the New World originated in Angola. The vast majority of these slaves ended up on the other side of the Atlantic Ocean in Portuguese Brazil.
I thought this episode was great. I really enjoyed the part about the Sokoto Caliphate which was the second largest slave society in the world. In 1900, the Sokoto Caliphate in northern Nigeria still had around 2.5 million slaves. Slavery endured in Africa long after it was abolished in the New World. In fact, it still exists in some countries like Mauritania and Sudan. I know Guinea had slavery well into the French colonial era. It was only abolished by the force of European public opinion.