Count de, Marquis de Sternay, Baron de Bronsac, was born at Paris in 1692. He was the eldest of the two sons of John Count de Caylus, lieutenant general of the armies of the king of France, and of the marchioness de Vilette. The count and countess, his father and mother, were very careful of the education of their son. The former instructed him in the profession of arms, and in bodily exercises; the latter watched over and fostered the virtues of his mind, and this delicate task he discharged with singular success. The countess was the niece of Madame de Maintenon, and was remarkable both for the solidity of her understanding and the charms of her wit. She was the author of that agreeable book entitled "The Recollections of Madame de Caylus," of which Voltaire lately published an elegant edition. The amiable qualities of the mother appeared in the son; but they appeared with a bold and military air. In his natural temper he was gay and sprightly, had a taste for pleasure, a strong passion for independence, and an invincible aversion to the ferocity of a court. Such were the instructors of the count de Caylus. He was only twelve years of age when his father died at Brussels in 1704. After finishing his exercises, he entered into the corps of the Miqueoires; and in his first campaign in the year 1709, he distinguished himself by his valour in such a manner, that Louis XIV. commended him before all the court, and rewarded him with an ensigncy in the Gendarmerie. In 1711 he commanded a regiment of dragoons, which was called by his own name; and he signalized himself at the head of it in Catalonia. In 1713, he was at the siege of Fribourg, where he was exposed to imminent danger in the bloody attack of the covered way. The peace of Rastadt having left him in a state of inactivity ill suited to his natural temper, his vivacity soon carried him to travel into Italy; and his curiosity was greatly excited by the wonders of that country, where antiquity is still fruitful, and produces so many objects to improve taste and to excite admiration. The eyes of the count were not yet learned; but he was struck with the sight of so many beauties, and soon became acquainted with them. After a year's absence, he returned to Paris with so strong a passion for travelling and for antiquities, as induced him to quit the army.

He had no sooner quitted the service of Louis, than he sought for an opportunity to set out for the Levant. When he arrived at Smyrna, he visited the ruins of Ephesus. From the Levant he was recalled in February 1717 by the tenderness of his mother. From that time he left not France, but to make two excursions to London. The Academy of Painting and Sculpture adopted him an honorary member in the year 1731; and the count, who loved to realize titles, spared neither his labour, nor his credit, nor his fortune, to instruct, assist, and animate the artists. He wrote the lives of the most celebrated painters and engravers that have done honour to this illustrious academy; and, in order to extend the limits of the art, which seemed to him to move in too narrow a circle, he collected, in three different works, new subjects for the painter, which he had met with in the works of the ancients.

Such was his passion for antiquity, that he wished to have had it in his power to bring the whole of it to life again. He saw with regret, that the works of the ancient painters, which have been discovered in our times, are effaced and destroyed almost as soon as they are drawn from the subterranean mansions where they were buried. A fortunate accident fur- nished him with the means of showing us the composition and the colouring of the pictures of ancient Rome. The coloured drawings which the famous Pietro Sante Bartoli had taken there from antique pictures, fell into his hands. He had them engraved; and, before he enriched the king of France's cabinet with them, he gave an edition of them at his own expense. It is perhaps the most extraordinary book of antiquities that ever will appear. The whole is painted with a purity and a precision that are inimitable; we see the liveliness and the freshness of the colouring that charmed the Caesars. There were only 30 copies published; and there is no reason to expect that there will hereafter be any more.

Count de Caylus was engaged at the same time in an enterprise still more favourable to Roman grandeur, and more interesting to the French nation. Colbert had framed the design of engraving the Roman antiquities that are still to be seen in the southern provinces of France. By his orders Mignard the architect had made drawings of them, which Count de Caylus had the good fortune to recover. He resolved to finish the work begun by Colbert, and to dedicate it to that great minister; and so much had he this enterprise at heart, that he was employed in it during his last illness, and warmly recommended it to M. Mariette.

In 1742, Count Caylus was admitted honorary member of the Academy of Belles Lettres; and then it was that he seemed to have found the place for which nature designed him. The study of literature now became his ruling passion; he consecrated to it his time and his fortune; he even renounced his pleasures to give himself wholly up to that of making some discovery in the field of antiquity. But amidst the fruits of his research and invention, nothing seemed more flattering to him than his discovery of encaustic painting. A description of Pliny's, but too concise a one to give him a clear view of the matter, suggested the idea of it. He availed himself of the friendship and skill of M. Magault, a physician in Paris, and an excellent chemist; and by repeated experiments found out the secret of incorporating wax with divers tints and colours, and of making it obedient to the pencil. Pliny has made mention of two kinds of encaustic painting practised by the ancients; one of which was performed with wax, and the other upon ivory, with hot punches of iron. It was the former that Count Cayles had the merit of reviving; and M. Muntz afterwards made many experiments to carry it to perfection.

In the hands of Count Caylus, literature and the arts lent each other a mutual aid. But it would be endless to give an account of all his works. He published above 40 dissertations in the Memoirs of the Academy of Belles Lettres. The artists he was particularly attentive to; and to prevent their falling into mistakes from an ignorance of costume, which the ablest of them have sometimes done, he founded a prize of 500 livres, the object of which is to explain, by means of authors and monuments, the usages of ancient nations. In order that he might enjoy with the whole world the treasures he had collected, he caused them to be engraved, and gave a learned description of them in a work which he embellished with 800 copper-plates.

The strength of his constitution seemed to give him hopes of a long life; but a humour settling in one of his legs, which entirely destroyed his health, he expired on the 5th of September 1765, and by his death his family is extinct. The tomb erected to the honour of Count Caylus is to be seen in the chapel of St Germain l'Auxerrois, and deserves to be remarked. It is perfectly the tomb of an antiquary. This monument was an ancient sepulchral antique, of the most beautiful porphyry, with ornaments in the Egyptian taste. From the moment he procured it, he had destined it to grace the place of his interment. While he awaited the fatal hour, he placed it in his garden, where he used to look upon it with a tranquil but thoughtful eye, and pointed it out to the inspection of his friends.

The character of Count Caylus is to be traced in the different occupations which divided his cares and his life. In society, he had all the frankness of a soldier, and a politeness which had nothing in it of deceit or circumvention. Born independent, he applied to studies which suited his taste. His heart was yet better than his abilities. In his walks he used frequently to try the honesty of the poor, by lending them with a piece of money to get change for him. In these cases he enjoyed their confusion at not finding him; and then presenting himself, used to commend their honesty, and give them double the sum. He said frequently to his friends, "I have this day lost a crown; but I was sorry that I had not an opportunity of giving a second. The beggar ought not to want integrity."