In 1414 the emperor of Ming China received an unexpected gift: a living giraffe, which his courtiers hailed as a qilin, a creature of good omen. The town of Malindi, on the coast of what is now Kenya, sent a giraffe to the Chinese court in 1414, by way of an embassy from Bengal, and Chinese fleets under Zheng He soon visited the East African coast themselves. The episode is a reminder that this coast was, for centuries, one of the hinges of a trading world that ran from Africa to China.

The monsoon world

The Indian Ocean has a rhythm. From roughly November to March the winds blow from the northeast, and from roughly April to September from the southwest. Because the monsoon winds reverse with the seasons, traders could sail between East Africa and India or Arabia and back within a year. Ships called dhows carried African gold, ivory, mangrove timber, ambergris and enslaved people north and east, and brought back Indian cloth, glass beads, Persian pottery and Chinese porcelain.

Swahili towns

Along some 3,000 kilometers of coast, from southern Somalia to Mozambique, grew dozens of trading towns: Lamu, Malindi, Mombasa, Zanzibar, Kilwa and many smaller ones. Their people came to call themselves Swahili, from an Arabic word for coasts. Swahili is a Bantu language with many Arabic loanwords; its grammar and core vocabulary are African, while words for trade, religion and learning often came from Arabic. Islam spread along the coast from about the eighth and ninth centuries, and the towns built mosques and houses of coral stone.

Who founded these towns? Colonial-era scholars, and some Swahili family traditions claiming descent from Persian princes, credited Arab or Persian colonists. Excavations from the 1980s onward, notably at Shanga in the Lamu archipelago, told a different story. Archaeology shows that the Swahili towns grew from local African communities, beginning as villages of timber and mud houses that slowly became stone towns as their people prospered and converted, while welcoming merchants who married in.

Kilwa

The richest town for a time was Kilwa, on an island off southern Tanzania. From the late thirteenth century its rulers controlled the gold trade through Sofala, the port that served the gold-producing plateau of the interior. Sultan al-Hasan ibn Sulaiman built a great palace, Husuni Kubwa. Kilwa minted its own copper coins, a mark of commercial confidence. Ibn Battuta, visiting in 1331, called it one of the most beautiful and best-built towns he had seen.

That prosperity drew predators. Vasco da Gama reached Malindi in 1498 and found a pilot there to guide him to India. Portugal then set out to seize the Indian Ocean trade by force. In 1505 the Portuguese sacked Kilwa to seize the gold trade, and sacked Mombasa the same year.

Great Zimbabwe

Where did Kilwa's gold come from? From the plateau between the Zambezi and Limpopo rivers, where an earlier kingdom centered on Mapungubwe flourished from about 1075 to 1220. Its successor built the largest stone ruins in sub-Saharan Africa. Great Zimbabwe was built by ancestors of the Shona people, mostly between about 1200 and 1450; its name comes from Shona words for houses of stone. The Great Enclosure has walls up to about eleven meters high, made of granite blocks fitted together without mortar. The city's power rested on cattle and on control of gold sent to the coast, and its finds include Chinese porcelain, Persian pottery, glass beads, soapstone carvings of birds and even a coin from Kilwa. By the mid fifteenth century the site was largely abandoned, perhaps because of worn-out land and shifting trade, and power moved to successor states such as Mutapa.

European visitors refused to believe Africans had built it. In 1871 the German explorer Karl Mauch decided it was a copy of the Queen of Sheba's palace. But in 1905 the archaeologist David Randall-MacIver concluded that Great Zimbabwe was African and medieval, and Gertrude Caton-Thompson confirmed this in 1929.

Worked example: who owns a ruin?

The evidence settled the question by 1929, yet the myth survived for half a century, because it was useful. Cecil Rhodes's British South Africa Company, which took the territory in the 1890s, sponsored diggers who cleared away layers of soil and artifacts in search of a foreign builder, destroying evidence. Rhodesian settlers liked to believe that the land's greatest monument proved earlier outsiders had ruled it, which made their own rule seem natural.

After the white-minority government declared independence from Britain in 1965, officials pressed museums and guidebooks to avoid stating plainly that Africans had built the site. The archaeologist Peter Garlake, the country's inspector of monuments, left his post in 1970 rather than accept that pressure. When the country won majority rule in 1980, it took the name Zimbabwe and put a soapstone bird from the ruins on its flag.

The lesson cuts both ways. Settlers bent the past to justify domination; a new nation used the same ruin to build pride. The historian's task is to keep the evidence, the walls, the dated layers, the porcelain and the Kilwa coin, at the center, whatever any government wants it to say.