Gabrielle de Lioncourt is a character from The Vampire Chronicles, a set of books by Anne Rice. She first appears in The Vampire Lestat.
BEWARE: minor spoilers of The Vampire Lestat
Gabrielle is an napolitan lady, born in 1730 and married to a french nobleman, the Marquis de Lioncourt. She moved to Auvergne after her marriage and had seven children from him, but only three of them survived until adulthood. One of her sons is none other than Lestat de Lioncourt, our beloved vampire.
Gabrielle's life in the french château was frustrating. She had a few books to distract herself, but her husband was against education, dismissing it as dangerous. Without friends or close relatives, she was lonely and trapped. Her children were no comfort: very much like their father, with the exception of Lestat. His interest in theater and books brought them closer and she made it possible for him escape to Paris, where he became an actor.
By then her mortal life was almost spent. Worn out by bitterness and childbearing, Gabrielle makes her last journey to Paris, to see her beloved son before the pneumonia got the best of her.
Death, however, never came. She found Lestat very much changed, having been transformed into a vampire. There's no hesitation from her part when he gives her the Dark Blood, making her his companion. They stayed together in Paris for a while, discovering vampiric life and its wonders. Brave, cold and strong, Gabrielle could frighten even her son. She abandoned all female ways and posture to be "finally free."
She helps Lestat in his struggles with the parisian coven and, after the whole incident with Nicolas, travels with him for a while around Europe, Asia Minor and Egypt. But each night she yearned for the jungle and woods. She wanted to walk in African forests and go where no mortals could. Lestat, however, had no intention to leave the mortal world behind and thus they separate in 1790.
Gabrielle is no longer mentioned in the books until The Queen of the Damned and the rise of Akasha. Even though she plays a small part on this story, she does not appear in the movie The Queen of the Damned (a misguided attempt to accomplish the impossible!).