In 1756 their son and heir was born. At first he was known as the Duc d'Enghien but this was afterwards changed to Duc de Bourbon. The second child was a daughter, Louise de Condé, subsequently famed for her great intelligence and beauty. The Princess Charlotte de Soubise was a general favourite at Court; but in spite of her many social engagements she never neglected her maternal duties and always showed herself a most devoted wife and mother. The Prince, notwithstanding his domestic felicity, considered it his duty to add a "sprig of laurel" to the trophies of his glorious ancestor, the Grand Condé. He therefore joined the army and greatly distinguished himself during the Seven Years' War. In 1762 he gained the victories of Grinningen and Johannesberg. The sudden death of his wife the Princesse de Condé from an attack of diphtheria put an end to his conjugal happiness; but to Chantilly he always returned after his campaigns, so as to be in the old home and with his children. A highly cultured gentleman, he took intense interest in literature and scientific research, enriching with numerous volumes the library of the Château and adding thereto mineralogical and physiological collections of great value. His only son, Louis Henri Joseph de Bourbon, when just fifteen was affianced to Louise Marie Thérèse Bathilde d'Orléans, five years his senior and an intimate friend of his sister Louise. Even in those days of early marriages this union was considered abnormal, and it was at first arranged that the young couple should wait for a time. But the youthful pair threatened to elope unless they were allowed to marry that same year, so with "_un éclat de rire_" the King gave his consent. When Marie Antoinette as Dauphine visited Chantilly the grace and charm of the young Duchess, who presided over the brilliant fêtes given upon that occasion, were much admired. Louis Joseph, like the Grand Condé, was passionately devoted to the art of the stage, and his daughter-in-law, like so many great ladies of her time, was distinguished for her literary talents. She herself composed the comedies in which she, her husband, and her Royal guests took part. The theatre at Chantilly, celebrated for its elaborate decorations and beautiful scenery, was approached by a terrace adorned by forty-eight marble vases; whence a double staircase led through the Salon d'Apollon. Palm-trees formed an avenue before its entrance, and the back of the theatre opened upon the garden, where a statue of Diana surrounded by waterfalls stood in the background. Amongst the improvements in the gardens first introduced by this Prince was a "_Hameau_," which was erected long before that in the Petit Trianon at Versailles.