Evidence type: Documented history
A Swahili port city on an island off southern Tanzania that grew rich on Indian Ocean trade: gold and ivory from the interior for goods from Arabia, India and China. Kilwa minted its own coins from the 11th to the 14th century; Ibn Battuta visited in 1331–1332.
Example: the Great Mosque, built in the 11th century of coral and lime mortar and enlarged in the 13th, roofed with domes and vaults.