It is recorded as a custom of the time, but was never taught or approved by God. The Bible records the significant problems that arose from the practice.
Gen:22:24: And his concubine, whose name was Reumah, she bare also Tebah, and Gaham, and Thahash, and Maachah.
A concubine is a secondary wife.
"The Concubine's Children" was created in 1994 by Denise Chong.
The Russian Concubine was created in 2007.
The Concubine - novel - was created in 1966.
Fragrant Concubine was born in 1734.
The Magnificent Concubine was created in 1962.
The Concubine's Secret was created in 2009.
Fragrant Concubine died in 1788.
Concubine Qi died in -194.
The Russian Concubine has 517 pages.
The Concubine - novel - has 216 pages.
Hajar is the alternate spelling of Hagar, Sarah's Egyptian servant in the Bible. Hagar bore Ishmael when she was a concubine for Abraham, and Sarah dismissed her into the wilderness for this.
Hagar, who bore Ishmael, Abraham's first son. Some would say that Keturah was also a concubine of his and not a second wife as others believe. There is also a tradition that Hagar and Keturah were the same person (Rashi commentary, Genesis ch.25).