The glass used in the windows is mouth-blown full antique stained glass, nearly all of which came from Germany. It is important to note that while the glass was imported from Germany, the windows themselves were crafted in St. Louis, Missouri by Bavarian born artist and craftsman Emil Frei, who founded the Emil Frei Art Glass Company in 1898. The company, Emil Frei and Associates, is still in business today, with the fourth and fifth generations of the family continuing the work. More information about the Frei family and the company history can be found here.