Laura Mancini was a niece of Cardinal Mazarin. She was the eldest of the five famous Mancini sisters, who along with two of their female Martinozzi cousins, were known at the court of Louis XIV of France as the Mazarinettes. She married Louis de Bourbon, Duke of Vendôme, grandson of King Henry IV and was the mother of the great general the Duke of Vendôme.
The eldest of ten children, through the influence of her uncle, the personal advisor of Louis XIII of France, Laura and her family were invited to France, leaving Rome in 1653 following the death of her father along with their cousins Laura and Anna Maria. The family resided in the Palais Royal in Paris, home of Queen Anne and her sons Louis XIV and Philippe, Duke of Orléans.
Originally engaged to Louis Charles de Nogaret de La Valette, Duke of Candale, son of the Duke of Épernon, the match did not take place and she was instead married to Louis de Bourbon, Duke of Mercœur. The young Louis was the son of the Duke of Vendôme, himself an illegitimate son of Henri IV of France and the famous Gabrielle d'Estrées.
Laura married Louis at the Palais Royal in the French capital on 4 February 1651 and was thus became Duchess of Mercœur. Having married a legitimised prince of the blood, Laura was allowed the style of Serene Highness. However, she had a lower rank than that of her cousin the Princess of Conti who had married a legitimate prince. The young duke was instantly enamoured with his wife and his affections were returned. Three sons followed in quick succession the eldest of which being a famous commander in the wars of the Grand Alliance and Spanish Succession. Laura died as a result of childbirth to Jules César, named after his grandfather and the Cardinal, in 1657. Born on 27 January, the Duchess died a fortnight later on 7 February. Buried in Paris, her husband retired from public life to become a cardinal, ensuring his children's upbringing to Laura's sister the Duchess of Bouillon.