The stained glass window, which recalls the story of St. Juliana of Liege and her work toward the establishment of the Feast of Corpus Christi, was first installed in the Cathedral in 1952. Karl Hackert Company of Chicago produced it. It was removed in 1982 when the present Blessed Sacrament Chapel was built. In later years it was installed in St. Joseph Hall at the Cathedral. It shows St. Juliana in the habit of a 12th century religious. She is being shown a vision of the traditional procession honoring the Blessed Sacrament. An angel holds a scroll with the words from the Mass of Corpus Christi composed by St. Thomas Aquinas after the feast was proclaimed by Pope Urban in 1264.

Juliana was born in Retinnes near Liege, Belgium. Orphaned at age five, she grew up in an Augustinian convent, and there entered religious life. By the age of sixteen, she had developed a strong devotion to the Blessed Sacrament, and the belief that God was calling her to work for the establishment of a liturgical feast that would honor it. For twenty years she resisted the call, feeling unworthy of such a privilege.

When finally she began work for the approval of the feast, she met with persecution from her own superior but received support from the Bishop of Liege and Archdeacon James Pantaleon, later Pope Urban IV. It was he who eventually proclaimed the Feast of Corpus Christi in 1264. He asked an Italian Dominican, Thomas Aquinas, to write the Divine Office for the new feast. The first words of the sequence for the Mass of Corpus Christi "Lauda Sion Salvatorem," are shown on the scroll held by the angel. St. Juliana died in exile, a victim not only of persecution by her superiors, but also of war, poverty and ill health. Although the feast she worked to institute for the world was granted six years after her death, she remains one of the saints closely associated with the Blessed Sacrament.

The purpose of celebrating this special feast of Corpus Christi is to: to confirm the faith in the Sacrament; to strengthen the faithful and help them to develop a great love for the Sacrament; and to bring about reparation for the insults and lack of respect shown to the Sacrament.