“He (Mahmud) scattered the army of the Hindus in one attack and took Rai Jaipal prisoner. He carried him to the distant part of his kingdom of Ghazni and delivered him to an agent of the Slave Market (dalal-i-bazar). I heard that at the command of the king (Mahmud), the Brokers of the Market, (maqiman-i-bazar in the original) sold Jaipal as a slave for 80 Dinars and deposited the money realised by the sale in the Treasury.”

Hodivala, 192-93. quoted from Lal, K. S. (1994). Muslim slave system in medieval India. New Delhi: Aditya Prakashan. Chapter 3

In every campaign of Mahmud large-scale massacres preceded enslavement.
Utbi, E.D., II, 26. Minhaj, 607, n., 5. quoted from Lal, K. S. (1994). Muslim slave system in medieval India. New Delhi: Aditya Prakashan. Chapter 3

Tarikh-i-Firishta, by Muhammad Qasim Hindu Shah Firishta, Translated from the Urdu version of Tarikh-i-Firishta by Abdul Hai Khwajah, Deoband, 1983, pt. I, p. 125. In Goel S.R. Hindu temples What Happened to them
Quotes from Muslim medieval histories

Goel, Sita Ram (2001). The story of Islamic imperialism in India. ISBN 9788185990231

According to the Arab invaders who was Bhoja's enemy;[Kitsbul Alaq Al-Nafisa Part 4, Ibne Rustah]
About

The Tabaqat-i-Akbari translated by B. De, Calcutta, 1973, Vol. I, p. 3.

Letter 8.
Letters on the Equality of the Sexes and the Condition of Woman (1837)

Romila Thapar, quoted from Ayodhya: The Case Against the Temple (2002) by K. Elst.

Source: No Treason (1867–1870), No. VI: The Constitution of No Authority, p. 24; the first sentence here is widely paraphrased as: A man is no less a slave because he is allowed to choose a new master once in a term of years.
Context: A man is none the less a slave because he is allowed to choose a new master once in a term of years. Neither are a people any the less slaves because permitted periodically to choose new masters. What makes them slaves is the fact that they now are, and are always hereafter to be, in the hands of men whose power over them is, and always is to be, absolute and irresponsible.
The right of absolute and irresponsible dominion is the right of property, and the right of property is the right of absolute, irresponsible dominion. The two are identical; the one necessarily implying the other. Neither can exist without the other. If, therefore, Congress have that absolute and irresponsible lawmaking power, which the Constitution — according to their interpretation of it — gives them, it can only be because they own us as property. If they own us as property, they are our masters, and their will is our law. If they do not own us as property, they are not our masters, and their will, as such, is of no authority over us.
But these men who claim and exercise this absolute and irresponsible dominion over us, dare not be consistent, and claim either to be our masters, or to own us as property. They say they are only our servants, agents, attorneys, and representatives. But this declaration involves an absurdity, a contradiction. No man can be my servant, agent, attorney, or representative, and be, at the same time, uncontrollable by me, and irresponsible to me for his acts. It is of no importance that I appointed him, and put all power in his hands. If I made him uncontrollable by me, and irresponsible to me, he is no longer my servant, agent, attorney, or representative. If I gave him absolute, irresponsible power over my property, I gave him the property. If I gave him absolute, irresponsible power over myself, I made him my master, and gave myself to him as a slave. And it is of no importance whether I called him master or servant, agent or owner. The only question is, what power did I put into his hands? Was it an absolute and irresponsible one? or a limited and responsible one?