Safeguarding Swahili trade in the fourteenth and fifteenth centuries: a unique navigational complex in south-east Tanzania

Abstract

Seaborne trade underpinned the economy and society of east Africa's Swahili coast in the first part of the second millennium ad. Field study and examination of satellite images have led to the conclusion that a major construction effort was expressly conducted to safeguard shipping undertaking that trade. The purpose of causeways and platforms initially noted on the approaches to Kilwa Kisiwani Harbour has been reassessed on discovery that similar features extend for over 120km along the coast of south-east Tanzania. Located in relationship to the reef margin, these structures are believed to have been navigational aids for ships plying the gold-trading Sofala-Kilwa route in the early fourteenth or fifteenth centuries. Accordingly, they complement the Swahili urban architecture of the period in providing a unique inter-tidal stone architecture of worldwide significance in maritime history.