The
fort is said to be constructed on the historic site of Indraprastha (900BC)
by Humayun and Sher Shah. Covering a circuit of about a mile, the walls of the
fort have three gates and are surrounded by a mat fed by the river Yamuna.
The wall was built by Humayun while the buildings in the fort are attributed
to Sher Shar. The notable buildings that have survived in the fort are the Sher
Mandal and the Quila-I-kholina Mosque. Sher Mandal is a two storeyed octagonal
tower which was used by Humayun as his library. The mosque, built around 1541-42,
is a landmark in Indo Islamic architecture.
The architect has shown skill by enriching each part with moulding, bracketed
openings, marble inlay, carving and other establishments. A variety of materials
have also been used to construct the small mosque (168 x 44 feet). The entrance
arch is of marble, the spandrels of red sandstone studded with marble bossed,
the columns and pilasters of black and white marble.