By 1818, a new leader, Shaka, gained authority among the Nguni people. He created a formidable military force of regiments organized on lineage and age lines. Shaka's Zulu chiefdom became the center of a new political and military organization that absorbed or destroyed rivals. Shaka was assassinated in 1828, but his successors ruled over a still-growing polity.
African societies who sold slaves might keep women and children for their own uses. The Atlantic trade had an important demographic effect on parts of western and central Africa; the population there in 1850 might have been one half of what it would have been without the trade. The women and children not exported skewed the balance of the sexes in African-enslaving societies.