This feature was insisted upon by Chancellor Bowman. The architect, Klauder, objected due to the increased costs of this construction method. Bowman responded with the comment: "You cannot build a great University with fraud in it." Klauder considered the Commons Room to be his greatest achievement. Joseph Gattoni designed the stonework, much of which depicts western Pennsylvanian plant life. The walls are made of Indiana limestone and the floor is green Vermont slate. The wrought iron in the room, including the large gates leading to the elevators, was a gift from George Hubbard Clapp and was designed by the ironworker Samuel Yellin. Over the gates are two lines by Robert Bridges, from an untitled poem: Here is eternal spring; for you the very stars of heaven are new. Also located in the corridors surrounding the Commons Room are plaques featuring calligraphy designed and hand-cut in slate by Edward Catich, including one featuring a poem by Lawrence Lee titled "The Cathedral," as well as stained glass windows by Charles Connick. During finals in the winter, fires in the enormous fireplace are lit, to promote a comforting and pleasant atmosphere for the dozens of students typically found studying into the late hours. Nationality Rooms The Cathedral is home to 31 Nationality Rooms located on the first and third floors: 29 working classrooms and two rooms used mostly for display or occasional special events. Each nationality room is designed to celebrate a different culture that had an influence on Pittsburgh's growth, depicting an era prior to (or in the singular case of the French Classroom, just after) 1787, which is year of the university's founding and the signing of the U.S. Constitution. The Nationality Room programs began in 1926 when Bowman decided that he wanted to involve the community as much as he could in constructing the Cathedral, so he proposed that each nationality that had a significant number of people in Pittsburgh would be allowed to design their nationality's room for the Cathedral. Each group had to form a Room Committee, which would be responsible for all fundraising, designing, and acquisition. The university provided only the room and, upon completion, upkeep for perpetuity. All other materials, labor, and design were provided by the individual committees. These were sometimes aided by foreign governments and the rooms contain many authentic artifacts and materials from the country represented. A typical room on the 1st floor