Kilwa Kisiwani: Medieval Swahili Sultanate and Gold Port

Kilwa Kisiwani is a small island off the coast of southern Tanzania that was home to the richest of the medieval Swahili city-states. Between about 1000 and 1500, and above all in the 13th and 14th centuries, its sultans controlled the sea trade in gold from Sofala in Mozambique, minted their own coins and built some of the finest stone architecture in sub-Saharan Africa. Its ruins, including the Great Mosque and the palace of Husuni Kubwa, are today a UNESCO World Heritage Site.

Background: an island on the trade route

Kilwa lies on a sheltered island with a good harbour, close to the southern limit that ships from Arabia and India could reach and return from in a single monsoon season. That made it a natural staging post between the northern Swahili ports and the gold market at Sofala further south.

Archaeological excavations, especially those led by Neville Chittick between 1958 and 1965, show that the island was settled by the 9th century by people who used local pottery and traded for imported wares. Stone building and a more urban settlement developed from the 11th century onwards, as part of the wider growth of the Swahili coast city-states.

The Kilwa Chronicle and the Shirazi founders

Kilwa’s early history is told in the Kilwa Chronicle, which survives in an Arabic text and in a Portuguese summary published by the historian João de Barros in 1552. According to the chronicle, a prince named Ali ibn al-Hasan, one of seven sons of a ruler of Shiraz in Persia, sailed to East Africa and bought the island from a local king in exchange for cloth.

Historians do not take this story literally. Copper coins naming Ali ibn al-Hasan have been found along the coast, and archaeologists now date him to around the 11th century. The claim of Persian descent, known as the Shirazi tradition, is widely seen as a way for a local Muslim elite to assert prestige rather than as evidence of mass migration from Persia.

Gold, coins and the Mahdali dynasty

Kilwa’s fortunes rose when it gained control of the trade with Sofala, the outlet for gold mined on the Zimbabwe plateau, the heartland of Great Zimbabwe. Gold, together with ivory, was carried north by Kilwa’s merchants to be sold to traders from Arabia and India, while Kilwa took customs duties on every cargo.

In the later 13th century a new ruling family, the Mahdali, whose ancestors were said to come from Yemen, took power. Under sultans such as al-Hasan ibn Sulayman, who ruled in the early 14th century and was known by the title Abu al-Mawahib, “father of gifts”, Kilwa reached its height.

Kilwa minted copper coins in the names of its sultans, and a few gold coins are also known. A Kilwa copper coin has been found at Great Zimbabwe, and in 1944 Kilwa coins were found on the Wessel Islands off northern Australia, though how they got there remains unknown.

Great Mosque and Husuni Kubwa

The Great Mosque of Kilwa began as a smaller prayer hall, probably in the 11th century, with a flat roof on timber columns. In the early 14th century it was greatly enlarged with a new hall roofed by a series of domes and vaults supported on columns, making it one of the largest mosques of the medieval East African coast.

On a headland outside the town, the same period saw the building of Husuni Kubwa, a vast palace and trading complex with courtyards, an octagonal bathing pool and storerooms. Its story is told in Husuni Kubwa: The Sultan’s Palace at Kilwa. Builders used coral stone, lime mortar and carved coral decoration, and set imported Chinese and Islamic bowls into ceilings and walls.

Ibn Battuta’s visit

The Moroccan traveller Ibn Battuta visited Kilwa around 1331 during his voyage down the East African coast. He described Kilwa as “one of the most beautiful and well-constructed towns in the world” and praised Sultan al-Hasan ibn Sulayman for his piety and generosity and for his raids against non-Muslim neighbours on the mainland.

His account is one of the few eyewitness descriptions of the town at its peak and is discussed more widely in the article on Ibn Battuta’s Travels.

Decline and the Portuguese

From the later 14th century Kilwa faced dynastic quarrels, competition from other towns and changes in the gold trade. Husuni Kubwa appears to have been left unfinished or abandoned soon after it was built.

In 1500 the Portuguese navigator Pedro Álvares Cabral called at Kilwa, and in 1502 Vasco da Gama forced its ruler to pay tribute. In July 1505 a fleet under Francisco de Almeida attacked and sacked the town, installed a puppet ruler and built a fort. The Portuguese abandoned the fort in 1512, but Kilwa never regained its former position. It revived somewhat under Omani influence in the 18th century, when the Makutani palace was built.

Key people

• Ali ibn al-Hasan: the founder figure of the Kilwa Chronicle, remembered as a prince from Shiraz; coins in his name suggest a real ruler of around the 11th century.
• Al-Hasan ibn Sulayman (Abu al-Mawahib): the most famous Mahdali sultan, ruler during Kilwa’s peak in the early 14th century and host to Ibn Battuta.
• Ibn Battuta: the Moroccan traveller whose visit provides the main eyewitness description of the town.
• Francisco de Almeida: the first Portuguese viceroy of India, whose fleet sacked Kilwa in 1505.
• Neville Chittick: the British archaeologist whose excavations from 1958 to 1965 established the modern understanding of the site.

Life in the town

At its height Kilwa was a town of stone houses for the elite, surrounded by a larger area of houses built of earth, wood and thatch. Wealthy households owned imported Chinese porcelain and Islamic glazed bowls, wore imported cloth and ate rice, fish and fruit. Merchants, sailors, craftsmen and enslaved workers made up much of the population.

Kilwa also influenced smaller towns nearby. The ruined town of Songo Mnara, on a neighbouring island, was built mainly in the 14th and 15th centuries and contains well-preserved houses, mosques and cemeteries. Archaeologists working there have uncovered details of daily life, from food remains to the use of open spaces for gatherings.

The ruins today

The ruins of Kilwa Kisiwani include the Great Mosque, the Small Domed Mosque, the palace of Husuni Kubwa, the complex known as Husuni Ndogo, the Portuguese-era fort known as the Gereza, and the 18th-century Makutani palace. Together with Songo Mnara they were inscribed as a UNESCO World Heritage Site in 1981.

Coastal erosion, vegetation and decay of the coral-stone walls threatened the ruins, and the site was placed on the List of World Heritage in Danger in 2004. Conservation work supported by national and international partners led to its removal from the danger list in 2014.

Timeline

• c. 9th century: Earliest settlement on Kilwa Kisiwani.
• c. 11th century: Rule of Ali ibn al-Hasan; first phase of the Great Mosque.
• Late 13th century: The Mahdali dynasty takes power.
• c. 1310-1333: Reign of al-Hasan ibn Sulayman; Great Mosque enlarged and Husuni Kubwa built.
• c. 1331: Ibn Battuta visits Kilwa.
• 1502: Vasco da Gama forces Kilwa to pay tribute to Portugal.
• 1505: Francisco de Almeida sacks Kilwa and builds a fort.
• 1981: Kilwa Kisiwani and Songo Mnara become a UNESCO World Heritage Site.

Why it matters

Kilwa shows how an African island town could become a wealthy, literate and outward-looking Muslim state by linking the gold of the interior with the Indian Ocean world. Its ruins are among the clearest physical records of the Swahili golden age.