Around the second millenium, camels had become established in the Sahara region but disappeared again from the Sahara beginning around 900 BC.
The Persian invasion of Egypt under Cambyses introduced domesticated camels to the area.
Domesticated camels were used through much of North Africa, and the Romans maintained a corps of camel warriors to patrol the edge of the desert.
The stronger and more durable Dromedaries first began to arrive in Africa in the fourth century. It was not until the Islamic conquest of North Africa, however, that these camels became common. While the invasion was accomplished largely on horseback, the new links to the Middle East allowed camels to be imported en masse. These camels were well-suited to long desert journeys and could carry a great deal of cargo. For the first time this allowed substantial trade over the Sahara.
Border guards in many remote desert locations in Egypt use camels for patrols. Such mounted border guards are called هجان Haggan (pl. هجانة Hagganah).