In the Mehrauli district of South Delhi, at the Qutub complex which is a conglomeration of archeological sites, a seventy-two metre tower rises over the neighbouring Quwwat-ul-Islam Mosque, the first mosque built in Delhi. This tower, the Qutub Minar, is the world's tallest brick minaret with 399 steps leading to the top. The diameter at the base of the minaret is 14.3 metres while the top floor has a diameter of 2.75 metres. The Qutub Minar was completed at the start of the thirteenth century by the new rulers of India—the Turkish slaves, Aibek and Iltutmish. Aibek laid the foundation stone for the minaret in 1199 but only managed to complete the first floor. His slave, Iltutmish added the subsequent three floors. In the fourteenth century, a fifth floor was added. The minaret was built using material from twenty-seven Jain and Hindu temples that stood at the site. Aibek and Iltutmish had the temples torn down and used the dismembered bricks, stones, and pillars of the temples to construct the minaret and accompanying mosque.

Military slaves were a unique feature of the political power structure in Islamic kingdoms. Rulers acquiring military slaves sought two qualities: military potential and malleability. As regards the first, hardy youth from nomadic tribes in rugged regions where only the fittest would survive were preferred. Youth from Central Asia met this requirement. As regards the second, non-Muslim boys of foreign origin between the age of twelve to fourteen were preferred.

The recruits would be converted to Islam, taught the language of their ruler and be trained in military skills. Being cut off from their original societies and with their destiny totally dependent on their new owners, these youth were easily moulded into soldiers with absolute loyalty to their rulers. A poet noted:

“One obedient slave is better than three hundred sons, for the latter desire their father's death, while the former, his master's glory.”

Qutb-ud-din Aibek was of Turkish origin and was born in Central Asia. As a child he was captured and sold as a slave to the chief judge of Nishapur, a town in Persia. Aibek was fortunate in that he was treated well by his master who gave him a good education which included archery and horsemanship.