http://www.india-delhihotel.com QILA RAI PITHORA The capital of Prithviraj Chauhan, Qila Rai Pithora, was the Delhi built in the 12th century as per available historical records. It is said that his ancestors had won the city from the Tomar Rajputs, who are credited with forming Delhi. Anangpal, a Tomar ruler, created the first known regular fort here and called it Lal Kot. Prithviraj Chauhan extended the city beyond the fort. The ruins of its ramparts are still visible around Qutub Minar and Mehrauli. The fort city of Siri The Khilji (or Khalji) rulers followed the Slave Dynasty. The most prominent among the six rulers was Alauddin Khilji, who extended his kingdom to the south of Narmada and also established the city of Siri. Among some of the remaining ruins is part of the Siri Fort in the greater Hauz Khas area. The madrasa at Hauz Khas was constructed during Alauddin's reign and bears the stamp of West Asian architecture. TUGHLAKABAD In 1330, Ghias-ud-din Tughlaq established the Tughlaq dynasty and set out to rebuild a Delhi of his own. His dream was to build an impregnable fort to keep away the Mongols. Thus he founded the city of Tughlakabad, the ruins of which still remain. His descendant Muhammad bin Tughlaq later formed Jahanpanah. Lying in the area between Siri and Qila Rai Pithora, this was the fourth medieval city of Delhi built in AD 1326–27.
"Historical Places of Delhi"