Explanation: The Delhi Sultanate was a significant Islamic empire that ruled large parts of the Indian subcontinent from the early 13th to the early 16th century. The Qutub Minar, located in Delhi, is one of the most iconic structures from this period, standing as a testament to the architectural prowess of the Delhi Sultanate.
Qutubdin Aibak, the founder of the Delhi Sultanate, initiated the construction of the Qutub Minar in the early 13th century. However, he did not live to see its completion. The task of completing the Qutub Minar was taken up by his successor, Iltutmish, who ruled from 1211 to 1236. Iltutmish not only completed the Qutub Minar but also added the fifth and final storey to the structure, giving it its current height of approximately 73 meters.
During Iltutmish's reign, the Delhi Sultanate faced a significant threat from the Mongol invasions led by Chengiz Khan. The Mongols, under Chengiz Khan, were expanding their empire across Central Asia and posed a serious threat to the stability of the Delhi Sultanate. Iltutmish, through his strategic military and diplomatic efforts, managed to save the Delhi Sultanate from the wrath of the Mongols. He established a strong defense system and maintained diplomatic relations with the Mongols, which helped in averting direct conflict and ensuring the survival of the Sultanate.
Iltutmish's reign was marked by significant administrative reforms and consolidation of power. He introduced the silver tanka, a standardized currency, and established a system of land revenue collection. His efforts in completing the Qutub Minar and defending the Sultanate from external threats solidified his position as one of the most important rulers of the Delhi Sultanate.
In summary, Iltutmish, as the correct answer, is recognized for his role in completing the Qutub Minar and saving the Delhi Sultanate from the Mongol invasions, making him a pivotal figure in the history of the Delhi Sultanate.