Question: In what year was Louis Joseph de Frances's mother born?
Related documents: [0]  [DOC] Marie Antoinette ( ; ] ; born Maria Antonia Josepha Johanna; 2 November 1755 – 16 October 1793) was the last Queen of France before the French Revolution. She was born an Archduchess of Austria, and was the penultimate child of Empress Maria Theresa and Francis I, Holy Roman Emperor. [END] 
[1]  [DOC] Louis Joseph de France (Louis Joseph Xavier François; 22 October 1781 – 4 June 1789) was the second child and elder son of King Louis XVI of France and Marie Antoinette. As son of a king of France, he was a "fils de France" ("Son of France"), and as the eldest son and heir apparent, he was Dauphin of France, (the twenty-sixth "crown prince" of the Capetian and Bourbon monarchies). [END] 
Answer: 
1755
1755