European lithophanes were first produced nearly at the same time in France, Germany, Prussia, and England around the later part of the 1820s. Many times historians credit Baron Paul de Bourging (1791–1864) with inventing the process “email ombrant” (pottery decorating) of lithophanes in 1827 in France. Robert Griffith Jones acquired Bourging’s rights in 1828 and licensed out to English factories to make them. The English factories sometimes used the name “lithophane” for specimens of ordinary “email ombrant. Some say however it was Georg Friedrich Christoph (1781–1848) of Prussia that actually perfected the true lithophane process in 1828. Others say the technique was developed in Berlin and other parts of Germany by such manufacturers as Königlichen Porzellan-Manufaktur and Porzellanmanufactur. This is why sometimes lithophanes are referred to as “Berlin transparency. There is a well known mark of Ad’T’ on lithophanes from Rubles, near Melun in France. It is thought to be the mark of Baron A. de Tremblay, however some scholars on the subject think he only made earthenware and not true lithophanes and the mark belongs to a yet unknown source.