Kilwa Kisiwani

Kilwa Kisiwani, "Kilwa on the island", is a small island off the coast of Lindi Region in southern Tanzania, and the site of the ruined capital of the Kilwa Sultanate. Between the thirteenth and fifteenth centuries this Muslim trading city was the most powerful place on the Swahili coast, controlling the gold trade from the interior and minting its own coins. Its coral-stone Great Mosque and the remains of the vast palace of Husuni Kubwa are among the finest monuments of medieval East Africa, and together with nearby Songo Mnara the island has been a World Heritage site since 1981.

Radiocarbon dating shows a settlement on the island from the early ninth century, and until the thirteenth century its buildings were of wattle and daub. Local tradition, recorded in later chronicles, credits the founding of the city to Ali ibn al-Hassan, a prince said to have come from Shiraz in Persia, who bought the island from a mainland king and married into the local ruling family. The tradition places him in the tenth or eleventh century, and even in its own telling the island was already inhabited. Historians treat these stories with caution: the city's roots were African, and there is no evidence of the Shia Islam of Shiraz on the coast. A 2023 ancient-DNA study nonetheless found that many medieval coastal townspeople had African mothers and largely Persian male ancestors, with the two groups mixing from around 1000.

Kilwa's rise came from trade carried on the monsoon winds. In the late twelfth century, according to the chronicles, Sultan Suleiman Hassan took control of Sofala, in what is now Mozambique, the port for gold and ivory coming from the interior, including Great Zimbabwe. The city exported gold, ivory, tortoiseshell, incense and cotton cloth and imported beads, textiles, porcelain and spices. Its coins, struck for roughly five centuries from about 1100, have turned up across the region.

Around the end of the thirteenth century power passed to the Mahdali dynasty, of Yemeni Arab descent. Its sultan al-Hasan ibn Sulaiman enlarged the Great Mosque, first built in the twelfth century with a flat roof on timber columns, probably adding the great dome Ibn Battuta later described, and raised Husuni Kubwa on a bluff above the sea: a palace and trading complex of more than a hundred rooms with courts and an octagonal pool. It seems to have been occupied only briefly and was never finished. The traveller Ibn Battuta, who came around 1331, praised the sultan's piety and generosity and the city's beauty, while also recording his raids inland for slaves and plunder. By the fifteenth century Kilwa claimed authority over towns from Malindi and Mombasa to Zanzibar, the Comoros and Sofala, though in practice it led a loose confederation of trading cities.

By the late fifteenth century the sultanate was weakened by powerful ministers who made and unmade rulers. In 1502 Vasco da Gama brought a fleet to Kilwa and forced the ruling emir to pay tribute, and in July 1505 Francisco de Almeida landed about 500 soldiers, sacked and burned the city, installed a client sultan and built a fort. Portuguese trading restrictions and the factional fighting that followed emptied much of the town, and the Portuguese Empire's garrison did not remain long.

The Gereza fort that stands on the island today may have Portuguese origins, but its present form is typical of Omani forts, and it may have held enslaved people in the late eighteenth and nineteenth centuries. In 1776 Kilwa's ruler agreed to supply a French merchant with 1,000 slaves a year. The old city was deserted by the 1840s, and from 1886 to 1918 the island was part of German East Africa.

Neville Chittick, appointed in 1957 as Tanganyika's first conservator of antiquities, excavated at Kilwa and removed human remains that were later stored in Nairobi; they were returned to Tanzania in 2016 and 2023. Erosion and plant growth threaten the ruins, and parts of Husuni Kubwa have been lost at the cliff edge. UNESCO placed the site on its List of World Heritage in Danger in 2004, and after conservation work, much of it supported by the World Monuments Fund from 2008, it was removed from the danger list in 2014. Much of the site has still not been excavated, and about 1,150 people live on the island today.