Directly across from the "Living Flame of Love" window is the "Interior Castle" window. This window is an artist rendition of St. Teresa of Avila's spiritual classic the "Interior Castle". St. Teresa of Avila, whom we consider our Holy Mother, reformed the Carmelite Order in the 16th century. The Interior Castle was one of several written works, which are considered spiritual classics in mystical theology, by this Doctor of the Church.
In the Interior Castle, St. Teresa guides souls to spiritual perfection in describing much of what she has experienced. St. Teresa envisioned the soul like a "castle made of a single diamond...in which there are many rooms, just as in heaven there are many mansions". She describes the 7 rooms that a soul must pass to experience suffering, strife and purgation in order to reach the inner chamber where perfect union with God exists.
In the window you will notice seven rings of which each pertains to the first through seventh mansions. The center of the mansions shows a triangle, which represents the Most Holy Trinity in the inner chamber.