Qutbud-Din Aibak laid the foundation of the world famous Qutb Minar in A.D. 1199, intended possibly
as a tower of victory but also as a minar attached to Quwwat-ul- Islam Masjid for the use of the muazzin (crier) to call the faithful to prayer. Qurbu'd-Din had perhaps only succeeded in raising the first storey, which was completed by his successor Iltutrnish (A.D. 1201- 35). It was later repaired by Firuz Shah Tughluq (A.D. 1351-88) and Sikandar Lodi (A.D. 1489-1517), according to the inscriptions on its surface. It has a diameter of 14.32 m at the base and about 2.75 m at the top with a height of72.5 m and 379 steps.