Concubinage a system under which a man keeps woman other than his legal wife in his household establishment for sexual and other domestic purposes. Though at present, the system is practically non-existent and socially unacceptable, concubinage was a recognised institution in Bengal till the end of the nineteenth century.

In the ancient texts, there are references to concubines in the households of kings and ruling classes. Even holy figures were known to have been maintaining concubines. Vidur, an important character in the epic mahabharata, was the son of a concubine. Sri krishna had hundreds of gopis who used to have sports (keli) with him. Concubines constituted an important element in royal harems throughout the history of Bengal.
In the royal courts, concubines had many roles to play, entertainment being the most important one. They often exerted considerable influence on their masters. Lutfun-Nisa, a concubine of Nawab sirajuddaula, had practically enjoyed the status of a Begum. Nawab Mir Jafar';s concubine, Munni Begum, who became his wife, wielded considerable power in the durbar. Her minor son, Nazimuddaulah, was nominated to be the nawab of Bengal by Mir Jafar.
As in the royalties and aristocracies, concubinage was commonly practiced by zamindars and other landholders. Many rich peasants also used to maintain concubines. The children of concubines were not equal members of the family and whatever rights they had were more customary than statutory. The social status of the concubines in the households of the zamindars, jotedars and other rich peasants was little better than that of slave girls. [Sirajul Islam] [Islam, Sirajul  Chief Editor, Banglapedia]