III. The Postclassical Period, 500–1500 > D. Africa, 500–1500 > 2. Regions, 500–1000 > d. East Africa
  The Encyclopedia of World History.  2001.
d. East Africa
The interior was not yet greatly involved with the coastal commerce. The most important changes in the interior in this period concerned the introduction of the banana and the development of highland agriculture based on it, and the spread of iron technology. The dominant groups (in terms of language) were the Cushites, who had entered the region between 3000 and 2000 B.C.E., and the Bantu, who had spread through the area in the first centuries C.E. Nilotes, Khoisan, and central Sudanic groups were also present. Cushites were cattle keepers and grain cultivators, while Bantu peoples practiced forest agriculture based on the yam, and therefore were concentrated in the wetter regions. During this period they began to adopt cattle and grain agriculture from their neighbors in the eastern part of the region. By the 7th century, Bantu dialects were diverging, indicating an end to the great sweep of migration and expansion by separate groups within more limited areas.  1
The interlacustrine region saw a buildup of population along the western and southwestern shores of Lake Victoria, leading to expansion to the northwest and north, settling the protopopulations of later communities such as the Ganda, Soga, Nkore, and Bunyoro. Iron tools slowly expanded in the interior, supplanting the earlier stone technology. Bantu groups made iron tools from the beginning of the Christian era. Such tools were also acquired in coastal trade by Cushites.  2
The processes leading to the development of Swahili culture on the coast accelerated in this period. Most important were the expansion of trade, the emergence of urban centers on the coast, and the beginnings of Islamic influence. The monsoon winds of the northern Indian Ocean region and the equatorial current, flowing south along the coast from Somalia, facilitated development of maritime trade linking India, Persia, southern Arabia, and the East Africa coast from the era of the Greek and Roman Empires.  3
Maritime trade was greatly stimulated by the growth of the Arab Islamic Empire beginning in the 7th century. The East African coast began to export new goods, and coastal towns grew and fell on the strength of the trade. Islam came with small numbers of immigrant merchants from Arabia and Persia from the 8th century, most of whom settled on offshore islands. Islam was slowly adopted by coastal Africans involved in trade but did not become dominant until the 12th century. However, the influence of the immigrant traders led to the absorption of a large number of Arabic loanwords into the developing indigenous language, Swahili, in the Bantu group, and to the use of Arabic script for writing Swahili.  4
Many coastal urban centers emerged during the 9th and 10th centuries, but most did not become prominent until the 11th century.  5
A new type of agriculture emerged toward the end of this period, practiced on the highland slopes of the Pare Mountains by the proto-Chagga (a blend of Nilotes, Cushites, and Bantu) and based on intensive cultivation of bananas, probably introduced by Indonesian traders. Bananas also spread in this period from the south to the interlacustrine region and to Mt. Elgon. (See East Africa)  6
The Encyclopedia of World History, Sixth edition. Peter N. Stearns, general editor. Copyright © 2001 by Houghton Mifflin Company. Maps by Mary Reilly, copyright 2001 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.