The first modern humans are believed to have inhabited South Africa more than 100,000 years ago. South Africa's first known inhabitants have been collectively referred to as the Khoisan, the Khoekhoe and the San. Starting in about 400 AD, these groups were then joined by the Bantu ethnic groups who migrated from Western and Central Africa during what is known as the Bantu expansion. The Bantu tribes were mainly limited to the area north of the Soutpansberg and the northeastern part of South Africa until the later Middle Iron Age (1000-1300), after which they started migrating south into the interior of the country.