Later, a lofty arched screen was erected and the mosque was enlarged, by Shams-ud- Din Iltutmish (A.D. 1210 - 1235) and Ala-ud-Din Khalji. The Iron Pillar in the courtyard bears an inscription in Sanskrit in Brahmi script of fourth century A.D., according to which the pillar was set up as a Vishnudhvaja (standard of god Vishnu) on the hill known as Vishnupada in memory of a mighty king named Chandra. A deep socket on the top of the ornate capital indicates that probably an image of Garuda was fixed into it.