In 1644, some Bakhtiari tribes rebelled against Abbas II. The rebellion, however, was quickly suppressed by Saru Taqi. Saru Taqi led a drive against corruption and, as a result, made many enemies. On 11 October 1645 he was assassinated by a group of army officers. Abbas II then appointed Khalifa Sultan as his grand vizier on 14 October. Khalifa Sultan had at first declined the offer, but shortly afterwards accepted. His established bureaucratic proficiency and past knowledge were definitely the deciding factors in this reappointment, albeit it may be possible that Abbas II recalled him into service in part with the goal of suppressing the discontent about the scarcity of the positions given to men of religion under his predecessor.