St. John of the Cross (or San Juan de la Cruz, 1542-1591) was born Juan de Yepes in Toledo, Spain, the youngest child of poor silk weavers. In prayer, St. John of the Cross was told to serve God through an order whose ancient perfection he was to help revive. He joined a Carmelite monastery in Medina, and followed the Carmelite rule to the strictest letter.

He met St. Theresa of Avila, who had decided to found an order of nuns in Medina, and she persuaded John to help her found a monastery in the primitive Carmelite rule in Valladolid, where he took the name John of the Cross. They were called the Reformed or Discalced (Barefoot) Carmelites. From the beginning he met with great opposition from many leaders, and spent months in prison, where he wrote some of his most beautiful poetry. As opposition grew and illness took hold, John was sent to the monastary of Ubeda, where he was initially treated very harshly. Eventually, however, even his adversaries acknowledged his sanctity. John was beatified in 1625 by Clement X, and canonized in 1726 by Benedict XIII. He was also declared a Doctor of the Church.

St. John of the Cross wrote a great deal of prose and poetry. He was a mystic who wrote about receiving God by emptying the soul of all else, including the self. He was not an academic, although his writings were heavily influenced by Sacred Scripture, the Summa of St. Thomas Aquinas, and of course the theology and writings of St. Theresa of Avila, his co-reformer. Interestingly, however, there is no evidence of influence by the fathers of the church, Pseudo-Dionysius the Areopagite, Hugh of St. Victor, or other important medieval mystics. This is why John's writings are said to evince an "empirical mysticism." His theology is not full of philosphical abstraction or logical deductions derived from Church tradition; rather, John wrote about what he knew from experience.

The principal writings of St. John of the Cross are:

The poetry of St. John of the Cross is considered some of the most beautiful ever written in the Spanish language, religious or secular.

The feast day of St. John is December 14. He is the patron saint of the contemplative life, contemplatives, mystical theology, mystics, and Spanish poets. His prayer is:

Saint John of the Cross, in the darkness of your worst moments, when you were alone and persecuted, you found God. Help me to have faith that God is there especially in the times when God seems absent and far away. Amen

For more see the node: negative theology.