When St. Catherine of Siena 91347-1380) was six years old, she beheld a vision of Christ above the Church of St. Dominic. The Fathers of the Desert, in turn, inspired her to begin practicing penances. Her adolescent ascetic practices aroused opposition in her parents, since they had plans for Catherine to marry. She resisted their wishes.

By 1363, she was vested in the black and white habit of St. Dominic, having become a Dominican tertiary - a devout woman who lives as a religious recluse. For three years she lived as a recluse in her own home, speaking only to her confessor the entire time. Following this period, Catherine began to reach out to her community, ministering to the sick and needy. In 1370, Catherine experienced a deep mystical state in which she died, only to return to life with a command to go into the world and save souls. By 1374, she had elicited the suspicion of the church because of her mysticism and followers. Being determined "not guilty" of heresy by church fathers, Catherine continued to work with those who had been struck by plague. On April 1, 1375, she experienced a stigmata, symbolized in the chapel window by her raised hands. The stigmata is the symbolic presence of the nail holes in the hands and feet of Christ exhibited in human beings.

Her extended mystical theology was in the form of a dialogue between herself and God. She died at age 33 after months of great physical suffering. In Catherine's window is the fleur de lys, symbolic of the victory of the Christian over temptation.