It was a custom as old as time itself: when rulers found they could not trust implicitly their nobility, which wallowed in its feuds and vested interests, power was secured by obtaining slaves cut away from their own roots and loyal to masters who provided them protection and a purpose. In Egypt, Turkey, Persia and indeed in India, the formula had been applied many times over – the first kings of the Delhi Sultanate themselves were military slaves belonging to Muhammad Ghuri, the invader.
