Qubbat-ul-Islam mosque, also known as the Qutb Mosque or the Great Mosque of Delhi was built by Qutb-ud-din Aybak, founder of the Mamluk or Slave dynasty.
It was the first mosque built in Delhi after the Islamic conquest of India and the oldest surviving example of Ghurids architecture in Indian subcontinent.
The mosque is built on a raised and paved courtyard, measuring 141 ft. X 105 ft, surrounded by pillared cloisters added by Iltutmish between 1210 and 1220 AD.
The mosque is in ruins today but indigenous corbelled arches, floral motifs, and geometric patterns can be seen among the Islamic architectural structures.
Web : http://en.wikipedia.org/wiki/Qutb_complex