Northern Wei in 399. Americas The Olmecs were the first major Indigenous American culture, with some smaller ones such as the Chavín culture amongst mainly hunter-gatherers. The Olmecs were limited by the dense forests and the long rainy season of the Olmec heartland, as well as the lack of horses. Post-classical era Africa The coast of East Africa contained a string of trading cities connected to kingdoms in the interior. The Horn of Africa was dominated by the Ethiopian Empire by the 13th and 14th centuries. South from it were the Swahili cities of Mogadishu, Mombasa, Zanzibar, Kilwa, and Sofala. By the 14th century, Kilwa had conquered most of the others. It also engaged in campaigns against the inland power of Great Zimbabwe. Great Zimbabwe was itself overtaken in trade by its rival, the Kingdom of Mutapa. Towards the north, the Empire of Kitara dominated the African Great Lakes in the fourteenth and fifteenth centuries. Towards the Atlantic coast, the Kingdom of Kongo was of regional importance around the same time. The Gulf of Guinea had the Kingdom of Benin. To the north, in the Sahel, there was a tripartite competition between the Mossi Kingdoms, the Songhai Empire, as well as the Mali Empire, with the latter declining in the fifteenth century. Americas The Tiwanaku Polity in western Bolivia based in the southern Lake Titicaca Basin. Its influence extended into present-day Peru and Chile and lasted from around 600 to 1000 AD. Chimor was the political grouping of the Chimú culture that ruled the northern coast of Peru beginning around 850 and ending around 1470. Chimor was the largest kingdom in the Late Intermediate period, encompassing of coastline. The Aymara kingdoms in turn were a group of native polities that flourished towards the Late Intermediate Period, after the fall of the Tiwanaku Empire, whose societies were geographically located in the Qullaw. They were developed between 1150 and 1477, before the kingdoms disappeared due to the military conquest of the Inca Empire. Beginning around 250 AD, the Maya civilization develop many city-states linked by a complex trade network. In the Maya Lowlands two great rivals, the cities of Tikal and Calakmul, became powerful. The period also saw the intrusive intervention of the central Mexican city of Teotihuacan in Maya dynastic politics. In the 9th century, there was a widespread political collapse in the central Maya region, resulting in internecine warfare, the