Many of Du Fay's books were bought by Count d'Hoym, who lived for many years at Paris as ambassador from Augustus of Poland and Saxony. The Count has been accused of showing bad manners at Court, and of bad faith in giving the trade secrets of Dresden to the factory at Sevres; in bibliography at any rate, he was supreme among the amateurs, and his White Eagle of Poland appears upon no volume that is not among the best of its kind. He sat at one time at the feet of the Abbe de Rothelin; but he soon became his master's equal in matters of taste, and was accepted until his exile at Nancy as the arbiter of elegance among the Parisians. M. Guigard quotes from the dedication of a 'treasury' of French poetry a passage that indicates his high position: 'To the poets in this assemblage, whoever they be, it is a glory, Monseigneur, to enter your Excellency's library, so full, so magnificent, so well chosen, that it is justly accounted the prodigy of learning.' Charles d'Orleans, Abbe de Rothelin, had died in 1744, when most of his books became the property of the nation. In some respects he was the most distinguished of the book-collectors. His learning and wealth enabled him to make a collection of theology that has never been surpassed; and he had the good fortune to acquire the vast series of State Papers and the priceless mediaeval MSS. collected by Nicolas Foucault. His special taste was for immaculate editions in splendid bindings; but nothing escaped his notice that was in any way remarkable or interesting. Paul Girardot de Prefond was a timber-merchant who fell into an apathetic state on retiring from active business. His physician, Hyacinthe Baron, was an eminent book-collector, and he advised the patient to take up the task of forming a library. So successful was the prescription that the merchant became renowned during the next half century for his superb bindings, his specimens from Grolier's stores, and the Delphin and Variorum classics which he procured from the library of Gascq de la Lande. On two occasions the sale of his surplus treasures made an excitement for the literary world. Some of his rarest books were sold in 1757, and twelve years afterwards his Delphin series and the greater part of his general collection were purchased by Count Macarthy.