In 1533 second Mughal Emperor began construction of a fortified city called Dinpanah, ‘the asylum of the faith’, the present day Old Fort or Puana Quila. Within a year the wall, gates and bastion were completed and city was fortified.
However the three main gates on the north, south and west are part of the fortifications of the Purana Qila, the sixth city of Delhi, built by Sher Shah Suri (1538–45). Sher Shah Suri raised his citadel after demolishing Dinpanah, the city built by Humayun. The fortifications of the Qila extended to a boundary of (2 km (1.2 mi)) on an irregularly oblong plan. Bastions adorned the corners and the western wall. Of the existing three gates, the west gate forms the entrance to the Qila and is called the Bara Darwaza (big gate). All three gates are double–storied structures built with red sandstone and have chhatris.