The East African coast is an interface between the continental world of Africa and the maritime world of the Indian Ocean, and the monsoons provided a convenient wind system to link them. It was inhabited by a littoral society that was best placed to play a leading role in economic, social, and cultural interaction, including intermarriage, between the two worlds. Its written history goes back at least to the beginning of the Contemporary Era, and it can be termed Swahili from the beginning of the second millennium when this branch of the Bantu languages spread down the coast to give it linguistic unity. Its speakers were organized in towns and villages from southern Somalia to northern Mozambique, which developed into city-states when there were major upturns in international trade and were integrated in the wider Indian Ocean world. The citizens spoke an “elegant” language that was further embellished through its interactions with Arabic and other Indian Ocean languages and literature. Islam spread with that trade, and mosques became a prominent part of the archaeological remains along the Swahili coast. In the process, the Swahili became thoroughly cosmopolitan. Any attempt to disentangle the different strands, “oriental” or “African”—which are two sides of the dense cultural fabric of the littoral people—is bound to be futile. They are two sides of the Swahili coin. This civilization was partially disrupted by the entry of the Portuguese in the 16th century when they tried to divert the spice trade to their channel around the Cape of Good Hope, but it revived during the 18th and 19th centuries.