"In an era when great civilizations enjoyed full glory and grandeur, culture and refinement eluded these desert rulers entirely, and if they had any occupation besides murder and robbery, it was guarding trade routes and escorting commercial caravans. Thus although old empires such as those of Egypt, Babylon, Persia, and Rome did not covet these wastelands, they took the desert rulers into their service for the sake of ensuring the safety of their own trade convoys."