Known as the 'Old Fort' of Delhi, the Purana Qil'a, the first Mughal capital city, is situated on the eastern edge of Delhi, along the river Jumna. Humayun, the second Mughal emperor (r. 1530-56) began constructing a walled city and fortress on this site in 1533, and named it 'Din-Panah', or 'Refuge of Religion'. The chosen site was an ancient area known as 'Indraprastha', associated with the Hindu epic Mahabarata. The original name for the fortress was 'Dinpannah', or 'asylum of the faith'. The project was not interrupted when he was temporarily deposed by Sher Shah Sur (r. 1540-55), for Sher Shah completed the fortress walls and built two important structures that were used by Humayun when he took back his throne and the city.
The fort walls are over one mile long, and contain three gates. The buildings that survive from the time of Sher Shah were built close to the western gate. They include the Qala-i-Kuhna Masjid, and the Sher Mandal, a three-storeyed, octagonal pavilion. The simple geometric plans, elegant massing, and red and white color scheme are characteristic of Mughal precedents, and like other Indo-Islamic buildings, they display some Hindu forms and decorations within an Islamic style. Although it is believed that the fort contained many more buildings by Humayun, none of them have survived.
Tillotson, G.H.R. 1990. Mughal India. San Francisco: Chronicle Books, 37-42.