Qila Rai Pithora was the 'first city of Delhi' dating back to 10th century. This city was established by Prithviraj Chauhan, also known as Rai Pithora. Prithviraj's ancestors captured Delhi from the Tomar Rajputs who have been credited with founding Delhi. Anangpal, a Tomar ruler possibly created the first known regular defense - work in Delhi called Lal Kot, which Prithviraj took over and extended for newly created city. The ruins of the fort ramparts are still partly visible in the area around Qutab Minar.