Alexandre Marie Léonor de Saint - Mauris de Montbarrey Alexandre Marie Eleonor of Saint - Mauris , count of Montbarrey , then prince of Montbarrey and of the Holy Roman Empire ( 1774 ) , grandee of Spain of first class ( 1780 ) , knight of the Holy Spirit , lieutenant general ( 1780 ) , born in Besançon on 20 April 1732 . He belonged to a family from Franche - Comté ( Dole ) , ennobled in 1537 by letter of the Emperor Charles V in the person of Jean of Saint - Mauris , doctor of Law , professor at the University of Dole and counselor at the parliament of Dole , and finally chief of the State Council of the Netherlands under Charles V and Philip II . The prince of Montbarrey was very proud about the origin of the nobility of his family and imbued with his titles of prince and grandee of Spain newly acquired ( he paid 100 , 000 pounds for his title of prince of the Holy Roman Empire granted by the Emperor Joseph II ) , had been making a fake genealogy linking his family to the family of Saint - Moris - Salins , another family of old nobility from the same county . The prince of Saint - Mauris - Montbarrey was the only son of lieutenant - general Claude Francois Elenonor of Saint - Mauris , count of Montbarrey ( 1694 - 1751 ) and Mary Therese Eleanor du Maine du Bourg ( 1711 - 1732 ) . After an early and distinguished military career , the prince of Montbarrey came to the court of the king Louis XVI where he was protected by his parent Madame of Maurepas , wife of the marquis of Maurepas , prime minister of Louis XVI . Through her husband , Madame of Maurepas managed to appoint Montbarrey as director of war ( position created especially for him without specific assignment ) and deputy of the count of Saint - Germain , secretary of State for war . At the resignation of the count of Saint Germain , thanks to the influence of Madame of Maurepas , Montbarrey was appointed in 1778 as Secretary of State for war . The prince of Montbarrey was an opportunistic and incompetent minister , without morality who involved more energy in his interests and lust with many mistresses than to conduct his department . In 1780 , during the war with America , he had to leave his department following criticism of Necker on the use of military founds and the scandal raised by the revelation of a traffic of military appointments hold by his mistress miss Renard . After his forced resignation , he moved with his wife and his daughter , the princess of Nassau - Saarbrücken to the Arsenal near the Bastille , in a luxurious building given by the king with a considerable pension . At the Revolution the furniture , library , gallery of paintings and art objects that decorated the residence of the prince of Montbarrey were seized as property of emigrants and sold to Lord Chattam ( eldest son of British Prime Minister William Pitt ) who took them to England . During the storming of the Bastille , the prince of Montbarrey and his wife escaped the massacre by the crowd . At the beginning of the Revolution , he took refuge in his castle of Ruffey near Besançon . In 1791 he emigrated with his wife in Switzerland in Neuchâtel and in the villages of Cressier and Landeron ( when they cross the border they had been robbed of all the money and jewelry they had with them ) . In January 1795 he moved to Constance where he died on 5 May 1796 in poverty . Upon his death , his widow returned from emigration and lived in Dole in Franche - Comté until his death in 1819 . The prince of Montbarrey wrote autograph Memories ( published in 1826 ) , where pages after pages it extends on his genealogy , his relationships and energy to take advantage of his position as minister to advance his fortune and personal interest ( in exchange for a refund by the royal treasury of the amount of three millions of doubtful debts of war claimed by the prince of Nassau - Saarbrücken , the prince of Montbarrey organized in 1779 the marriage of his daughter 20 years old with the crown prince of Nassau - Saarbrücken aged just 11 years ) The prince of Montbarrey married on 29 October 1753 Parfaite Thais Françoise of Mailly - Nesle ( born in 1737 , died in Dole on 23 April 1819 . ) Montbarrey and his wife had little affinity ( he had throughout his life many mistresses and she was the mistress of the famous Masson of Pezay ( 1741 - 1777 ) , soldier and writer ) . The prince of Montbarrey and his wife had two children : The prince of Montbarrey had an official mistress during eight years ( 1767 - 1775 ) Jeanne Catherine Delachaux ( born in Brussels on 4 May 1748 , died in Paris on 4 May 1818 ) who married at 27 years on 26 July 1775 the painter François Casanova , brother of the famous Casanova . She brought a dowry thanks to the generosity of the prince of Montbarrey . François Casanova recognized the two illegitimate children of the prince of Montbarrey as his own . The marriage did not last because François Casanova abandoned his wife in 1783 . One of the two illegitimate children of Jeanne Catherine Delachaux and the prince of Montbarrey recognized by François Casanova was known as Alexandre Benoit Jean Dufay , Casanova ( born in Paris in 1770 , died in Paris in 1844 ) . He had as teacher the famous painter David , but did not get a great success . At the end of his life , he took the title of painter of the King of Oudh ( India ) to have been the official painter of this monarch in Lucknow from 1834 to 1837 . His brother ( also illegitimate son of the prince of Montbarrey ) emigrated and joined the army of the princes abroad before returning to live in Paris where he died before 1844 . We don ’ t know whether the two sons of the prince of Montbarrey and Jeanne Catherine Delachaux had descendants . Maximilienne of Saint - Mauris - Montbarrey , princess of Nassau - Saarbrücken , daughter of the prince of Montbarrey , died on 2 February 1838 in Maisons - Alfort ( near Paris ) , aged 79 years old . She was the last of his family and of the name of Saint - Mauris - Montbarrey . His heir was his cousin the duke of Avaray .