A change in style was first experienced on the arrival in power of Madame de Pompadour, who led the way in that coquettish return to simple conditions of life which showed itself in the pastorals of the Louis Quinze epoch. It resulted in a preference for simple gold; this metal, coloured by alloys such as platinum and silver, and popular under the name of _à quatre couleurs_, being at most only set off by enamel painting. This later rococo period, as far as its technique is concerned, is one which has never been equalled either before or since. An event of importance in the history of jewellery, as of art generally, was the discovery in 1755 of the city of Pompeii, succeeding that in 1713 of Herculaneum, buried for centuries beneath the ashes of Vesuvius. The journeys of artists to Italy and to Naples, and the interest aroused thereby in ancient art, a weariness with the mannerism of rococo ornament, and the whim of fashion, gradually transformed jewellery like other decorative arts, and resulted in the classicism of the style of Louis XVI. Antique forms as they then were known showed themselves in a very charming manner in well-balanced jewels, where different coloured gold took the form of classical motives in the midst of ribbons, garlands, and the pastoral subjects dear to the previous epoch. Enamel returned into fashion, and accomplished its chief triumph with painting _en plein_ in fine transparent tones over _guilloché_ gold. In conjunction with the art of gem setting and cutting, and metal chasing, this species of enamel produced effects which were all the more surprising, seeing that it was often confined to the smallest of spaces. Among the first craftsmen who created, or followed the fashion, was the jeweller Lempereur. Some of his designs were published by his pupil Pouget the younger in 1762 and 1764, in a treatise entitled _Traité des pierres précieuses et de la manière de les employer en Parure_, the plates of which, mostly coloured, and representing models of jewellery of all kinds set with precious stones, were engraved by Mlle. Raimbau. Another pupil of Lempereur, August Duflos, published in 1760 a similar work entitled _Recueil de Dessins de Joaillerie_. Other French designers of jewellery at this time were: Maria, a jeweller of Paris, who issued about 1765 an important series of plates, thirty-five in number, of pendants, brooches, clasps, chatelaines, aigrettes, seals, rings, and buckles; P. Moreau (1740-1780) and J. B. Fay (1780-1790), both of Paris; and L. Van den Cruycen (1770) of Brussels.