“All sultans were keen on making slaves, but Muhammad Tughlaq became notorious for enslaving people. He appears to have outstripped even Alauddin Khalji and his reputation in this regard spread far and wide. Shihabuddin Ahmad Abbas writes about him thus:
“The Sultan never ceases to show the greatest zeal in making war upon infidels… Everyday thousands of slaves are sold at a very low price, so great is the number of prisoners”. Muhammad Tughlaq did not only enslave people during campaigns, he was also very fond of purchasing and collecting foreign and Indian slaves. According to Ibn Battuta one of the reasons of estrangement between Muhammad Tughlaq and his father Ghiyasuddin Tughlaq, when Muhammad was still a prince, was his extravagance in purchasing slaves. Even as Sultan, he made extensive conquests. He subjugated the country as far as Dwarsamudra, Malabar, Kampil, Warangal, Lakhnauti, Satgaon, Sonargaon, Nagarkot and Sambhal to give only few prominent place-names. There were sixteen major rebellions in his reign which were ruthlessly suppressed. In all these conquests and rebellions, slaves were taken with great gusto. For example, in the year 1342 Halajun rose in rebellion in Lahore. He was aided by the Khokhar chief Kulchand. They were defeated. “About three hundred women of the rebels were taken captive, and sent to the fort of Gwalior where they were seen by Ibn Battutah.” Such was their influx that Ibn Battutah writes: “At (one) time there arrived in Delhi some female infidel captives, ten of whom the Vazir sent to me. I gave one of them to the man who had brought them to me, but he was not satisfied. My companion took three young girls, and I do not know what happened to the rest.” Iltutmish, Muhammad Tughlaq and Firoz Tughlaq sent gifts of slaves to Khalifas outside India….. Ibn Battutah’s eye-witness account of the Sultan’s gifting captured slave girls to nobles or arranging their marriages with Muslims on a large scale on the occasion of the two Ids, corroborates the statement of Abbas. Ibn Battutah writes that during the celebrations in connection with the two Ids in the court of Muhammad bin Tughlaq, daughters of Hindu Rajas and those of commoners, captured during the course of the year were distributed among nobles, officers and important foreign slaves. “On the fourth day men slaves are married and on the fifth slave-girls. On the sixth day men and women slaves are married off.” This was all in accordance with the Islamic law. According to it, slaves cannot many on their own without the consent of their proprietors. The marriage of an infidel couple is not dissolved by their jointly embracing the faith. In the present case the slaves were probably already converted and their marriages performed with the initiative and permission the Sultan himself were valid. Thousands of non-Muslim women were captured by the Muslims in the yearly campaigns of Firoz Tughlaq, and under him the id celebrations were held on lines similar to those of his predecessor. In short, under the Tughlaqs the inflow of women captives never ceased.”

Lal, K. S. (1994). Muslim slave system in medieval India. New Delhi: Aditya Prakashan. Chapter 5 (quoting Masalik-ul-Absar, E.D., III, 580., Battutah)