The Sultanate under Iltutmish established friendly contacts with the Abbasid Caliphate between 1228–29. He had managed to keep India unaffected by the invasions of Genghis Khan and his successors.Following the death of Iltutmish in 1236, a series of weak rulers remained in power. The throne shifted from Rukn ud din Firuz to Razia Sultana until Ghiyas ud din Balban, the last powerful ruler of this dynasty. The Khalji dynasty was established, when Jalal ud din Firuz Khalji overthrew the last of the Slave dynasty rulers, Muiz ud din Qaiqabad, the great grandson of Balban.