A Swahili coastal settlement on an island off southern Tanzania, radiocarbon-dated by excavation to the start of the 9th century AD — one of the earliest Swahili trading towns, alongside Shanga and Unguja Ukuu (both already in the dataset). It later became the seat of the Kilwa Sultanate under the Shirazi dynasty (traditionally 10th-11th century), which at its height (13th-15th c.) controlled trade along the entire Swahili coast, including the Sofala gold trade.
Grew from an early trading settlement into the medieval Kilwa Sultanate's capital; sacked and occupied by the Portuguese in 1505, beginning its long decline. (The Kilwa Sultanate as a distinct political entity is not yet separately modeled in this dataset — recommend a follow-up record for a later era bucket, c. 1000-1500.)
The primary excavation report for Kilwa Kisiwani, by the archaeologist who led the definitive digs there — polity-specific, not a survey.