St. John of the Cross represents the pinnacle of Spanish mysticism. In contrast to St. Teresa's works, which refer frequently to things of this world, St. John's poetry works on a purely spiritual, abstract plane. His poems consist of allegorical descriptions of the journey of his spirit through mortification of earthly appetites, illumination, and purification of the soul to union with God. In his prose commentaries on his own poems he laments the insufficiency of language to communicate his mystical experiences and his interior life. A disciple of St. Teresa, he became the spiritual director of her convent at Avila in 1572 and was responsible for carrying out many of her rigorous new programs for the Carmelite Order. Objections to his extreme reforms led to a period of imprisonment and torture in Toledo. During this time, according to tradition, he wrote Spiritual Canticle. His concentrated symbolic poetry has been studied with enthusiasm by such modern poets as T. S. Eliot, Paul Valery, and Jorge Guillen.