The second daughter of Gabriel de Rochechouart, Duke of Mortemart and Diane de Grandseigne, she was a member of the House of Rochechouart, itself one of the most well regarded noble families in France. Her mother was a lady-in-waiting to Anne of Austria and as a young girl, she often travelled with her mother between the family estates and the court at the Louvre in Paris. At the age of twelve, she began her formal education at the Convent of St Mary at Saintes, From a young age she was styled as "Mademoiselle de de Tonnay-Charente" or "Mademoiselle de Mortemart". 