The Sevres Date Mark, is made from two lines that look like a cursive "L." One is the mirror image of the other and they cross to form a triangular cartouche. A letter inside the lines dates the porcelain. It has been used by the Sevres factory in Sevres, France, since 1753.Each year from 1753 to 1793 different letters and combinations of letters were rotated in and out of the cartouche. Letters were not in use from 1795 to 1801. A new set of date marks was adopted during France's First Empire (1804-1815) and was placed below the mark of a crowned eagle. Under Louis XVIII's reign (1814-1824) the cartouche was still used; but under later kings, republics, and empires, the cartouche shape was discontinued. Factories in England, Germany, France, and the United States copied this mark, causing confusion for collectors. Copies are still in use.