Which Turkish Sultan introduced the Iqta system?

Shams ud-din Iltutmish, the Sultan of the Mamluk/Slave dynasty of the Delhi Sultanate, formally institutionalized and distributed the Iqta system. Under this land-distribution and administrative framework, territories were partitioned and assigned to military commanders and nobles (called Iqtadars or Muqtis) in lieu of cash salaries, charging them with collection of revenue and upkeep of law and order.