Villeroy & Boch Pottery of Mettlach was founded in 1836. The firm made many types of wares, including the famous Mettlach steins. Collectors can be confused because although Villeroy & Boch made most of its pieces in the city of Mettlach, Germany, they also had factories in other locations. The dating code impressed on the bottom of most pieces makes it possible to determine the age of the piece. Additional items, including steins and earthenware pieces marked with the famous castle mark or the word Mettlach, may be found in the Mettlach category. Villeroy & Boch also made mosaic ware and chromolith ware.