The Cambridge History of India, Vol. III: Turks and Afghans v3.c29.s2.37

v3.c29.s2.37

A long line of princes of the Chauhān tribe had ruled the principality of Sāmbhar, of which Ajmer had become the chief town, and in the middle of the twelfth century Vigraharāja (Vīsaladeva or Bīsal Deo) of this line extended his dominions in an easterly direction by capturing Delhi from a chief of the Tomara tribe, who had founded the city in A.D. 993-94 by building the Red Fort where the Qutb Mīnār now stands. The city was of no great importance but Vigraharāja’s victory extinguished a minor dynasty and might have made for unity and strength, had there not been other competitors for power in the field.