Marshal de SOUBISE. Charles de Rohan, duc de Rohan-Rohan, prince de Soubise, comte de Saint-Pol, maréchal de France (1715-1787) 18th-century French soldier and minister. Autograph letter signed and addressed to Voltaire in 1751, thanking him for sending his latest books "Le Siècle de Louis XVI et de Louis XV". 4 1/2 pages in-8. "I have read, Monsieur, with the greatest attention, and the greatest pleasure the four volumes of Le Siècle de Louis quatorze et de Louis quinze, which you have kindly presented to me. I feel the value of everything that comes from your pen. You have treated the three articles you mention in your letter with favorable prejudice towards me. I am deeply touched. You emphasized the disadvantages of combined armies and the difficulty of uniting and reconciling the minds of second-rate officers when two generals share command. You're quite right. I, more than anyone else, have experienced such embarrassments and the unfortunate or unpleasant consequences they entail. I would, however, exclude the last campaign with Monsieur le Mal. d'Estrées. We have always lived and acted in perfect harmony, but I still believe that an army should be led by a single leader, and that he should avoid all obstacles that could lead to uncertainty in his operations...".