Franz Mayer & Co. (Mayer & Co. of Munich) is a famous German stained glass design and manufacturing company, based in Munich, Germany, that has been active throughout most of the world for over 150 years. The firm was very popular during the late nineteenth and early twentieth century and was the principal provider of stained glass to the large Roman Catholic churches that were constructed throughout the world during that period. Franz Mayer and Co. were stained glass artists to the Holy See and, consequently, popular with Roman Catholic clients.