Saint John of the Cross (1542 – 1591) was a reformer of the Carmelite Order and is considered, along with Saint Teresa of Ávila, as a founder of the Discalced Carmelites. He is best known for his mystical works.
He (and St Teresa) are witnesses to the potential and difficulties of reforming an existing order from within:
On the night of 2 December 1577, John was taken prisoner by his superiors in the calced Carmelites, who had launched a counter-program against John and Teresa's reforms. John had refused an order to return to his original house, on the basis that his reform work had been approved by the Spanish Nuncio, a higher authority than John's direct superiors in the calced Carmlites. John was jailed in Toledo, where he was kept under a brutal regimen that included public lashing before the community at least weekly, and severe isolation in a tiny stifling cell barely large enough for his body. He managed to escape nine months later, on 15 August 1578, through a small window in a room adjoining his cell. (He had managed to pry the cell door off its hinges earlier that day). In the meantime, he had composed a great part of his most famous poem Spiritual Canticle during this imprisonment; his harsh sufferings and spiritual endeavours are then reflected in all of his subsequent writings. The paper was passed to him by one of the friars guarding his cell.
After returning to a normal life, he went on with the reformation and the founding of monasteries for the new Discalced Carmelite order, which he had helped found along with his fellow St. Teresa de Ávila.
He died on 14 December 1591, of erysipelas (cellulitis).