In terms of mechanical devices, later Mughal emperor Babur provides a description of the use of the water-wheel in the Delhi Sultanate, which some historians have taken to suggest that the water-wheel was introduced to India under the Delhi Sultanate. However this has been criticized e.g. by Siddiqui, and there is significant evidence that the device existed in India prior to this. Some have also suggested that the spinning wheel was introduced to India from Iran during the Delhi Sultanate, though most scholars believe that it was invented in India in the first millennium. The worm gear roller cotton gin was invented in the thirteenth or fourteenth centuries: however, Irfan Habib states that the development likely occurred in Peninsular India, which was not under the rule of the Delhi Sultanate (except for a brief invasion by Tughlaq between 1330-1335).