The trans-Saharan slave trade, established in Antiquity, continued during the Middle Ages. The slaves brought from across the Sahara were mainly used by wealthy families as domestic servants, and concubines. Some served in the military forces of Egypt and Morocco. For example, the 17th century sultan Mawlay Ismail, himself was the son of slave, and relied on an army of black slaves for support. The West African states imported highly trained slave soldiers. It has been estimated that from the 10th to the 19th century some 6,000 to 7,000 enslaved people were transported north each year. Perhaps as many as nine million enslaved people were exported along the trans-Saharan caravan route.