The Sahara formed a formidable barrier between the Mediterranean world and the Sudan, but it was not an impassable void. For roughly five and a half centuries, caravans crossed it regularly, year by year, connecting settled peoples on its northern and southern margins. Caravan towns served as ports and harbours, while sparse desert populations supplied camel breeders, guides, carriers, and sometimes predators who preyed upon the traffic.

The exchange was economically consequential on both sides. Sudanese gold supported the Mediterranean economy, while the central Sahara and Sudan were deeply involved in the slave trade. Customs duties enriched authorities in oasis settlements and Sudanic cities, and the slave trade strengthened emerging states by rewarding military power, tribute, and exchange while also adding population to societies south of the desert.

The main central route ran from Tripoli through the oasis network of the Fezzan to Kawar, whose water sources and salt industry made it an important stage, and then onward to Lake Chad. A shorter but harsher road ran from Egypt through Kufra and Tibesti to Borku and Lake Chad, while a western route passed through Ghat and Air toward Hausaland. These corridors transmitted merchants, slaves, Islamic learning, religious practices, and political influences, although local societies often absorbed and reshaped what arrived from outside.