"The art of making ceramic inclusions in crystal was discovered in France in 1780 by M. de Beaufort, director of St. Louis from 1775 to 1788. Between 1779 and 1782, Boyer and Phillippe Charles Lambert learned manufacturing secrets from a Bohemian glassmaker, Joseph Koenig, a defector from an English glassworks. They founded a glassworks in Sevres in 1783 under the patronage of Marie Antoinette. In 1785 this business was transferred to Montcenis, near Creusot, close to abundant deposits of coal, which at the time was a new source of fuel. This factory, called the Queen's, Montcenis', or Creusot's, was to become famous under the Empire and the Restoration for the quality of its crystal. It is credited with some exceptional sulphides." From "Classic French Paperweights" by Edith Mannoni.