The island city-state off the coast of present-day Tanzania that became the richest and most powerful of the medieval Swahili coast cities — a Muslim merchant town of coral-stone palaces and mosques that grew wealthy by controlling the export of African gold into the Indian Ocean world, until Portuguese sea power sacked it around 1505 and broke its hold on the trade.
Around 1331 a famous traveler from Morocco stepped ashore on a small island off the East African coast and judged it one of the most beautiful and best-built towns he had ever seen. Ibn Battuta had walked through Cairo, Damascus, and Mecca. Yet Kilwa impressed him. Its people lived in houses of coral stone, prayed in a great domed mosque, and traded in gold carried from deep in the African interior. The gold was the secret. A town that grew almost nothing of its own had made itself rich by standing at the right point on the ocean.