Answer:
In the XI century the need for slaves was driven primarily by the development of the Indian Ocean trade and the break of the Islamic Empire.
Explanation:
The African slave trade was dominated by Arab merchants, and as driven first by the trade of gold and slaves for manufactures. Along the XI century many minng operations were being conducted in Mali, Ghana, South Africa, Zanzibar and in the Muslim controlled areas of India. Also, the break of the Islamic Empire lead to the use of slaves as military units (the beginnng of the Mamluk system in Egypt).
