Everywhere in the ancient world the development of iron metallurgy was a revolutionary advance that permitted men to build new and more complex societies. Africa was no exception to this rule. It saw the rise of great African kingdoms equipped with a new mastery over the soil and the forest and over their non-iron-using neighbors. This ironwork was the product of home industries practiced for generations and which originally owed nothing to the white man. It is now known that great iron civilizations developed as early as the beginnings of the Christian era in at least two widely separated regions of the continent: One in West Africa (the Sudan, Dahomey, Ghana, etc.); another in eastern and south-central Africa. A few years ago it was hardly suspected that iron technology in south-central Africa dated back so far, but since 1953 evidence has been piling up with the discovery of early Christian-period iron centers near Lake Tanganyika and elsewhere. This article is the last of a series of four articles reprinted here to help develop a sense of perspective in the historical depth of African culture, and the early evidences of civilization in some parts of the continent.