For six hundred years, the Swahili city-states of the East African coast enjoyed a golden age that the world has largely forgotten. Cities like Gedi, Malindi, Pate and Mombasa were cosmopolitan, wealthy and cultured. Stone houses with ornate carved doors. Mosques with coral walls. Merchants who spoke five languages and traded with partners from China to Portugal. Swahili civilisation was not imported from Arabia. It grew here, on African soil, from African people who blended what they were with what arrived by sea.