the practical needs of the time became a feature of Turkic rule in Delhi. Legacy "Iltutmish laid down the foundation of the Delhi Sultanate as a truly independent kingdom, freeing it from a subordinate position to Ghazni. The Caliph's investiture, although a mere formality, reaffirmed his status as an independent sovereign among the Muslims. By the time of his death, the Delhi Sultanate had emerged as the largest and the most powerful kingdom in northern India. Iltutmish was most probably the first ruler to organize a centrally recruited, centrally paid and centrally managed army in the Delhi Sultanate. His courtier Fakhr-i Mudabbir composed Adab al-harb wa-l-shaja'a, a book on the art of warfare. Iqtas Iltutmish implemented the iqta system of administrative grants in the Delhi Sultanate. This system, borrowed from the earlier Islamic dynasties of the Middle East, involved dedicating the revenues from a certain region to a subordinate in exchange for military service and political loyalty. Iltutmish used this iqtas to consolidate his empire by dismantling the existing feudal order of the Indian society. Iltutmish assigned several regions to his Turkic subordinates in form iqtas. The larger iqtas - which were effectively provinces of the empire - were assigned to high-ranking men, who were expected to administer the regions, maintain local law and order, and supply military contingents in times of need. The holders of the smaller iqtas were only expected to collect revenues from their regions, in exchange for providing military service to the emperor. To ensure that this iqta system remained bureaucratic - rather than feudal - in nature, Iltutmish transferred the iqta holders from one region to another, refused to grant them legal immunity, and discouraged localism in administration. Both free amirs as well as bandagan-i-shamsi (as opposed to bandagan-i-khass during Mu'izz ad-Din's times) were used by Iltutmish over an extended, long process involving rotation of the iqtas assigned to each noble every once in a while to ensure that there was no question of claims on a specific region by a specific noble. Besides these, princes were used as well in almost the same capacity, but in more important roles. Coinage Iltutmish introduced two coins that became the basis for the subsequent coinage of the Delhi Sultanate: the silver tanka and the copper jital. His predecessors, including the Ghurid rulers, had maintained the local coinage system based on the Hindushahi bull-and horseman coins minted at