The geographical compartmentation of Afica helps to account for the restricted reach of ancient Egypt, whose influence does not appear clearly outside the Nile valley itself, and then only as far south as Nubia. About the Christian era, or perhaps shortly before, an important Indonesian component was brought into Africa. At that time, the island of Madagascar was colonized by a people who arrived by sea from one of the islands of Indonesia, perhaps from Borneo, where their closest linguistic relatives live in modern times Other Indonesian settlements probably once existed along the eastern coast. The surest evidence of this is that a number of root crops native to Indonesian and therefore well suited for rain-forest cultivation established themselves as staples of African agriculture. The new crops had their major impact on west Africa where cultivators began to penetrate into the vastnesses of the Congo rain forest about this time, perhaps because the new Indonesian crops first made agriculture in that environment practicable. The initial expansion of the Bantu-speaking peoples, whose original homeland and point of dispersion lay in west Africa, not far, perhaps, from the Bight of Ben in, may have depended on their successful exploitation of the new Indonesian crops.