It was built over the ruins of the Lal Kot, the citadel of Dhillika. Qutb-ud-din Aibak, a deputy of Muhammad of Ghor, who founded the Delhi Sultanate after Muhammad of Ghor’s death, started construction of the Qutb Minar’s first storey in 1199. This level has inscriptions praising Muhammad of Ghor. Aibak’s successor and son-in-law Shamsuddin Iltutmish completed a further three storeys. After a lightening srike in 1369 damaged the then top storey, the ruler at the time, Firuz Shah Tughlaq, replaced the damaged storey, and added one more. Sher Shah Suri also added an entrance while he was ruling and the Mughal emperor Humayun was in exile.