At the age of fourteen Marie Isabelle was married off to the son of the Duc de Tallard, Joseph d'Hossun de La Baume - her bridegroom was seventeen years her senior. Now that she was a married "woman" it became essential to get an appointment at court. This she gained as a member of Elizabeth Charlotte d'Orléans' - Madame - household,
Marie Isabelle was not completely alone in Madame's household since her grandmother, Charlotte de La Mothe-Houdancourt - or simply Madame de Ventadour - held the position of Governess to the Children of France. This position she retired from in 1735 and it was handed on to Marie Isabelle.
|Marie Isabelle de Rohan|
During her position as Governess Marie Isabelle had a close relationship with the royal family; particularly Queen Marie Leczynska who doted on her many children. In turn Marie Isabelle was made lady-in-waiting to Madame Henriette (second daughter of Louis XV) as well as the prestigious position of dame du palais to the Queen herself. Word has it that the Queen was very fond of her young companion which must have eased Marie Isabelle's position considerably.
With positions such as those Marie Isabelle was a firm fixture at Versailles where she was honoured with her own apartment. Here she hosted dinner parties which even the King was noted to frequently attend. The royal children themselves appears to have been pleased with Marie Isabelle for the Dauphin made sure that she was also appointed governess to his own daughters.
Despite spending a great portion of her time with children Marie Isabelle never had any of her own. Her marriage appears to have been a typical arranged marriage - the couple was not very close. Marie Isabelle remained at Versailles until her death on the night of 4 January 1754. Her loss was felt dearly by the royal family even those who had not been under her care for a great while.