The doctrine of Saint Catherine, who learned to read with great effort and to write when she was already an adult, is contained in the Dialogue on Divine Providence or the Book of Divine Doctrine, a masterpiece of spiritual literature, in her letters collected in the Epistolary, and her Prayers.

In a vision that remained indelibly impressed on her heart and mind, the Virgin Mary presented her to Jesus, who gave her a splendid ring, saying to her, “I, your Creator and Savior, wed you in the faith, which you will preserve ever pure until you celebrate your eternal marriage with me in heaven” (Raymond of Capua, Saint Catherine of Siena, Legenda major, no. 115, Siena 1998). This ring was and remained visible only to her. In this extraordinary episode we grasp the vital center of Catherine’s religious sense and of every authentic spirituality: Christocentrism. For her, Christ is like a husband, with whom there is a relationship of intimacy, communion, and fidelity. He is the good loved above every other good.

This profound union with the Lord is illustrated by another episode from the life of this illustrious mystic: the exchange of hearts. According to Raimondo da Capua, who recorded what Catherine told him in confidence, the Lord Jesus appeared to her holding a bright red human heart in His hand. He opened her chest, inserted the heart, and said to her, “Dearest . . .