Qutb Minar was established along with Quwwat-ul-Islam Mosque around 1192 by Qutb-ud-din Aibak, first ruler of the Delhi Sultanate. The mosque complex is one of the earliest that survives in the Indian subcontinent. The minaret is named after Qutb-ud-din Aibak, or Qutbuddin Bakhtiar Kaki, a Sufi saint. Its ground storey was built over the ruins of the Lal Kot, the citadel of Dhillika. Aibak's successor Iltutmish added three more storeys. The minar's topmost storey was damaged by lightning in 1369 and was rebuilt by Firuz Shah Tughlaq, who added another storey. In 1505, an earthquake damaged Qutub Minar; it was repaired by Sikander Lodi. On 1 September 1803, a major earthquake caused serious damage. Major Robert Smith of the British Indian Army renovated the tower in 1828 and installed a pillared cupola over the fifth story, thus creating a sixth. The cupola was taken down in 1848, under instructions from The Viscount Hardinge, then Governor General of India. It was reinstalled at ground level to the east of Qutb Minar, where it remains. It is known as "Smith's Folly".