This room is one of the most beautiful in the Cathedral and is the center of Scottish Rite ritual work, stage plays, and other entertainment.
It is 99 feet square, 45 feet high, and 175 feet from the rear of the stage to the back of the fourth floor balcony. The arena is 33 feet square and 15 inches below the stage area.
The stage is 33 feet deep and 84 feet wide, and has more than 50 scenic back-drops for various scenes of the 29 Scottish Rite degrees stored in the ceiling. They are operated by 12 miles of rope. The proscenium arch of the stage is 38 feet wide and 28 feet high.
The architecture is Cathedral Gothic, sometimes referred to as Medieval Gothic, and was patterned in large part after the details of the Cologne Cathedral.
The woodwork, panels and trim are Russian curly oak. The trusses and woodwork were stained in dark fumer oak. The wall panels are embellished in Gothic motif and are shaded from dark near the floor to lighter toward the ceiling. These symbolize how Scottish Rite teachings bring its members from darkness to light.
The carvings on the trusses and woodwork were created by the sons of Anton Lang. Lang was famous for playing the part of Christ in the passion play at Oberammergau, Germany. The four robust cherubs on each side of the theater and the two on either side of the stage holding plaques to their breasts are symbolic reference to the Ten Commandants.
About 1,100 persons can be seated in the theater and another 200 on chairs in the arena.
Description taken from A Guide to The Indianapolis Scottish Rite Cathedral by Alan G. Lisle, 33° and Charles G. Fromer, 33°