 Mancini was born on 28 August 1639 and grew up in Rome.Her father was Baron Lorenzo Mancini, an Italian aristocrat who was also a necromancer and astrologer.After his death in 1650, her mother, Geronima Mazzarini, brought her daughters from Rome to Paris in the hope of using the influence of her brother, Cardinal Mazarin, to gain them advantageous marriages.