Harem is a Muslim invention. No other religion accepts the concept of a harem. It is an exclusive place where the women are kept by the Muslim nobles or kings for their pleasure. In India the concept of Harem was brought in by the Muslim rulers who rule Hindustan for nearly 900 years. The harem and its ethos were imported from Turkey and Saudi Arabia and are sanctified by Islam.
The Muslims when they rule India believed in the Islamic law of multiple wives and concubines. But as rulers they thought it their right to have a number of Hindu Girls as part of their harem. Some of the girls were forcibly abducted and in some cases pressure was brought on the local Hindu kings to give their daughters to the Muslim Kings. Some of the local chieftains like the Rajputs willinglyave their daughters and princesses to the Muslim rulers in return for petty benefits. This dichotomy of the Rajputs has never been explained, for all their so called bravery that they acceded to the ruler's firman or order to marry their daughters into the Harems of the Muslim kings.
The Harem was a large place with an independent administration.The life was reasonably easy and comfortable, but the women were never allowed to go outside. Hindu women were forced to convert to Islam on threat of torture and death. But a few emperors like Akbar allowed their Hindu queens to continue their Hindu rituals inside the Harem or Zenena.
The Harems were guarded by eunuchs and no male was allowed inside, except the king or the ruler himself. The Harem was like a form of imprimementment and a lot many women who entered it left only once they died. However the older women and mothers were given greater respect.
The concept of the Harem is peculiar to Islam. The Mughal emperors kept hundreds of women in their Harems. Akbar reportedly had over 500 women. A lot many of them were Hindus. As the Hindus were a subjected lot they had no choice and in case an emperor liked or heard of the beauty of a Hindu princess, he would order that she be brought to his harem. In case the request was not compliant with he would take punitive measures against the local raja. But in variably, the Hindu Kings handed their daughters into the harems. This is certainly a sad comment on the state of affairs in India at that time. It was left to the British and the Raj to stop this practice and the Hindus could have heave a sigh of relief.