Never did Voltaire speak with more enthusiasm, and never was the feeling more generous and sincere. He had suddenly discovered among a crowd of other noble protectors a man of rare and unexpected power; and for some time the letters to d'Argenson are sufficient to show that he had sensibly risen in Voltaire's esteem. The praises he received were accompanied by a full and careful criticism, the hasty reading of which may have given rise to a gratuitous impeachment of the writer's sincerity. The suggestion will be presently considered;[254] here it is enough to say that it was no ordinary political work which, in 1739, could arouse the enthusiasm of Voltaire. A third episode in the correspondence is of some importance. It was through Voltaire that d'Argenson acquired his first knowledge of a man to whom he was afterwards introduced more intimately by events, the young Prince Royal of Prussia. Among other marks of regard, Voltaire sent him some of the prince's letters, and asked him to share his admiration. It may be imagined that d'Argenson, in whom devotion to royalty was hereditary, and whose regard for merit was always so keen, was not slow to echo the enthusiasm of his friend.[255] From this time forward he watched with lively and appreciative interest the development of Frederick's career, and upon the frequent letters which found their way into his hands he formed a conception of the Prince's character which was not without its influence upon future events. Its essence is contained in some words he wrote on hearing of Frederick's accession (June, 1740):-- "Il fera ce qu'il faudra faire."[256] His pleasure at the event is only qualified by the pitiful contrast presented by the King upon whom his hopes had so long been built. Such are the principal features of this delightful correspondence. It was continued with more or less intermission until the end of 1744, when d'Argenson found occasion to exercise his friend's pen in matters of more than epistolary weight. Throughout the difficulties of an arduous ministry, his task was lightened and his efforts cheered by the encouragement and co-operation of Voltaire. IV. NOVEMBER, 1744--JANUARY, 1747. Foreign Politics--D'Argenson's Ministry--1745: The Convention of Augsburg--The Convention of Hanover--The Imperial Election--The Treaty of Dresden--1746: The Negotiation of Turin--The Saxon Marriage--Review. At the end of 1740, d'Argenson had succeeded his brother as chancellor of the Orleans household;[257] in November 1744, he was invited to accept a place in the Government as Minister of Foreign Affairs.[258] His brother, Count d'Argenson, was already Minister of War, and since the dismissal of Amelot in April, had been signing the despatches of the Foreign Office.