The largest ancient stone construction south of the Sahara, Great Zimbabwe is believed to have been built between the twelfth and fifteenth centuries by the ancestors of the Shona, one of Zimbabwe's many Bantu-speaking groups. The ruins cover nearly 1,800 acres and can be divided into three distinct architectural groupings known as the Hill Complex, the Valley Complex, and the Great Enclosure. At its zenith in the late fourteenth century, Great Zimbabwe may have had as many as 18,000 inhabitants. It was one of some 300 known stone enclosure sites on the Zimbabwe Plateau. In Bantu, Zimbabwe means "sacred house" or "ritual seat of a king." An important trading centre and capital of the medieval Zimbabwe state, the city controlled much of interior south-east Africa for nearly two centuries.