gems, East Africa, Periplus

For some 2,000 years, ships from Arabia and north-western India have sailed to and from the East African coast, exploiting the alternating monsoon winds—blowing from the south-west for much of the year and from the north-east during a four-month season. These coasts, the southernmost region known to the ancients, are the only part of equatorial Africa for which we possess historical records predating the fifteenth century. This history is more closely connected to the Indian Ocean world than to the African interior, and although the sources are sparse, often corrupted, and partly mythical, they offer a tentative framework of events—one that must be verified, expanded, and sometimes corrected through archaeological evidence. While the northern coast was more accessible to early sailors, it was the lands south of the equator that held the greatest appeal to traders and settlers from the arid regions of the northern Indian Ocean—an appeal powerfully demonstrated in the nineteenth century when Sayyid Sa‘id bin Sultan moved his capital from Muscat to Zanzibar. From the Horn of Africa to Mogadishu, the coastline is barren, with few harbours and a dry hinterland. The Banadir coast, stretching from Mogadishu to just south of the equator near the Kenya–Somalia border, though more indented and harbour-rich, remains relatively poor. South of about 2° S, rainfall increases and the coastline becomes deeply indented with drowned river valleys. Numerous offshore islands, especially those with freshwater, provided safe bases for traders. These islands shield the coast, much of which is bordered by mangrove swamps, broken occasionally by steep sandy beaches with flat foreshores—ideal for landing. At high tide, boats could anchor and be conveniently unloaded after grounding on the receding tide. Between the islands, shallow coral shelves provided an abundant supply of fish, further supporting coastal life and trade.