Philippe was born in Rome in 1641. He was the son of Baron Lorenzo Mancini, an Italian aristocrat who was also a necromancer and astrologer. After his father's death in 1650, his mother, Geronima, brought her family from Rome to Paris in the hope of using the influence of her brother, Cardinal Mazarin, to gain them advantageous marriages. Philippe's five famous sisters were:
Soon after his arrival in France, his uncle, Cardinal Mazarin, decided to use him as a tool to avert future warfare in the kingdom. Upon the death of King Louis XIII in 1643, the older of his two sons succeeded to the throne of France as King Louis XIV. In order to discourage the type of tempestuous relationship that had developed between Louis XIII and his younger brother Gaston, duc d'Orléans, the young king's mother, Anne of Austria, and chief minister, Cardinal Mazarin, decided to protect the future king by making sure that his younger brother, the duc d'Anjou, had no part in any political or military office. During his youth, Anjou's behavior was closely watched by dowager queen and her advisor, who made sure that the young duke had no meaningful financial freedom from the Crown. His income was to be derived solely from his appanage. The queen and Mazarin discouraged the duc d'Anjou from traditional manly pursuits such as arms and politics, and encouraged him to wear dresses, makeup, and to enjoy feminine behaviour. His inclination toward homosexuality was not discouraged, with the hope of reducing any threat he may have posed to his older brother. Reportedly, Cardinal Mazarin even commanded his nephew, Philippe, to de-flower the king's younger brother. In 1657, Cardinal Mazarin re-established the Mousquetaires du Roi, a military unit later immortalized by Alexandre Dumas, père in his story of The Three Musketeers. Philippe was awarded the position of leader of the corps as a captain-lieutenant. In 1661, after the Cardinal's death, jurisdiction over the musketeers passed to Louis XIV. He replaced Philippe in 1667 with Charles de Batz-Castelmore, comte d'Artagnan. The comte had been in actual control of the unit since joining in 1658, as Philippe was not interested in war and rarely accompanied the musketeers in battle. As a young man, Philippe frequented the salon of Paul Scarron. Scarron's young wife, the future Madame de Maintenon, became friends with Philippe's sister Marie Mancini. In 1660, Philippe was nominated to be duc de Nevers and Donzy by his uncle, Cardinal Mazarin, with the prerogative to strike coins. The Parlement de Paris, however, refused to register this new creation. Another creation in 1676 was no more successful. In 1661, Philippe inherited part of his uncle's colossal wealth, the majority of which went to his younger sister, Hortense, who was their uncle's favourite. In 1668, Philippe helped Hortense escape her abusive husband by procuring horses and an escort to help her travel to Rome, where she took refuge with their sister, Marie, now the Princess Colonna. He was a knight of the Order of the Holy Spirit.
Diane Gabrielle Victoire Mancini, who married Charles Louis Antoine de Hénin-Liénard, prince de Chimay
Philippe Jules François Mancini, prince de Vergagne et du Saint Empire, then duke of Nevers
Diane Adélaïde Philippe Mancini, who married Louis-Armand, duc d'Estrées
Jacques Hippolyte Mancini, who in 1719 married Anne-Louise de Noailles, with their only child being Marie Diane Zéphirine, who married Louis-Héracle de Polignac. They are ancestors of Albert II of Monaco through their grandson, Jules François Armand de Polignac.
