John of the Cross (1542-1591), born Juan de Yepes y Álvarez, was a Spanish Catholic priest, mystic, and a Carmelite friar who was a converso (convert from Judaism). He is a major figure of the Counter-Reformation in Spain. On the night of 2 December 1577, a group of Carmelites opposed to reform broke into John’s dwelling in Ávila and took him prisoner. John had received an order from superiors, opposed to reform, to leave Ávila and return to his original house. John had refused on the basis that his reform work had been approved by the papal nuncio to Spain, a higher authority than these superiors. The Carmelites therefore took John captive. John was taken from Ávila to the Carmelite monastery in Toledo, at that time the order’s leading monastery in Castile, with a community of 40 friars.  John was brought before a court of friars, accused of disobeying the ordinances of Piacenza. Despite his argument that he had not disobeyed the ordinances, he was sentenced to a term of imprisonment. He was jailed in a monastery where he was kept under a brutal regime that included public lashings before the community at least weekly, and severe isolation in a tiny stifling cell measuring barely 10 feet by 6 feet. Except when rarely permitted an oil lamp, he had to stand on a bench to read his breviary by the light through the hole into the adjoining room. He had no change of clothing and a penitential diet of water, bread and scraps of salt fish. He managed to escape eight months later, on 15 August 1578, through a small window in a room adjoining his cell.

During his imprisonment, he composed a great part of his most famous poem Spiritual Canticle, as well as a few shorter poems. John of the Cross is known especially for his writings. He was mentored by and corresponded with the older Carmelite, Teresa of Ávila. Both his poetry and his studies on the development of the soul are considered the summit of mystical Spanish literature and among the greatest works of all Spanish literature. He was canonized by Pope Benedict XIII in 1726. In 1926 he was declared a Doctor of the Church by Pope Pius XI, and is commonly known as the “Mystical Doctor”.