Modern Zambia once was inhabited by the Khoisan and Batwa peoples until around AD 300, when migrating Bantu began to settle the areas. It is believed the Khoisan people originated in East Africa and spread southwards around 150,000 years ago. The Twa people were split into two groups: the Kafwe Twa lived around the Kafue Flats and the Lukanga Twa who lived around the Lukanga Swamp. Many examples of ancient rock art in Zambia, like the Mwela Rock Paintings, Mumbwa Caves, and Nachikufu Cave, are attributed to these early hunter-gatherers. The Khoisan and especially the Twa formed a patron-client relationship with farming Bantu peoples across central and southern Africa but were eventually either displaced by or absorbed into the Bantu groups.