Soon after the Arab conquest of Egypt, the Arabs attempted to conquer the kingdoms of Christian Nubia on multiple occasions, but utilizing strategic guerilla-like warfare, the significantly smaller Christian Nubia defeated the larger Arab forces. Eventually, given their unsuccessful efforts, the Arabs signed the 600-year Baqt treaty with the Christian Nubian kingdom of Makuria. As a part of the treaty, the Nubians, already involved in the burgeoning East African slave trade, agreed to trade 360 slaves annually to their northern neighbors in exchange for spices and grains.