On the east coast of Tanzania, south of Dar es Salaam, lies the tiny island of Kilwa Kisiwani. From the thirteenth to the fifteenth centuries the port city of Kilwa was the centre of trade for the entire Swahili coast, integrated in a trading network that stretched as far as Arabia, India and even China. The inhabitants of this beautiful city were ethnically mixed – including Persians, Arabs and Bantu-speaking Africans – and, over time, they developed a distinctive East African culture and language – Swahili, which literally means ‘coast dwellers’. This cultural influence stretched all along the East African coast, from Inhambane and Sofala in the south (modern-day Mozambique) to Mombasa and Malindi (Kenya) and Mogadishu (Somalia) in the north.

The trade network along the East African coast had ancient roots. Some Chinese records suggest trade connections between Africans and Chinese as far back as the Han dynasty in China (206 BCE–220 CE). But much of our evidence come from archaeologists who have excavated and analysed glass beads in East Africa