She was born at the Ducal Palace of Modena, the fourth daughter and eighth child of Francesco III d'Este, Duke of Modena, the Sovereign Duke of Modena and his young wife Charlotte Aglaé d'Orléans, Mademoiselle de Valois - granddaughter of Louis XIV of France and Madame de Montespan.
Maria Fortunata was known to have been very pious and at the same time rather timid but charming [REF].