“Whoever does not seek the cross of Christ doesn't seek the glory of Christ.”
Born as Juan de Yepes y Alvarez in Fontiveros, Avila, Saint John was a child of parents hailing from decendants of Jewish converts to Christianity and did not come from a lot of wealth. His father died in 1545 (Saint John was only 3) and his older brother Luis died in 1547 from malnutrition. Shortly after this death, his mother took Saint John and his younger brother Francisco to Medina del Campo for better job prospects in 1551. It was here in Medina that Saint John began his education, studying at a school for orphans and serving as a Altar Server at a nearby Augustinian nunnery. In 1563 he entered the Carmelite Order, taking the name John of Saint Matthias.
In 1567, Saint John was ordained a priest and on a journey from Salamanca to Medina del Campo in September 1567 met Saint Teresa of Avila. Though he had been considering joining the strict Carthusian order, Saint Teresa convinced Saint John to delay joining and to learn more about her Carmelite reforms (she was seeking to restore the purity of the Carmelite Order by reverting to the observance of it's Primitive Rule of 1209). Saint John immediately found this fascinating and appealing and travelled with her to Valladolid. In October of 1568, he left the town with Friar Antonio de Jesus de Heredia to found a new monastery following Teresa's reforms and principles. That day, November 28th, 1568, they procured a derelict house in Duruelo, established the monastery, and Saint John officially changed his name to Saint John of the Cross.
In 1577 a group of Carmelites opposed to the new reforms broke into Saint John's dwelling in Avila and took him prisoner. He was brought to the Carmelite monastery in Toldedo and accused of disobeying orders (Superiors in the order had demanded that he leave Avila as they were opposed to the reforms - Saint John ignored this order as his work had by then been approved by the Papal nuncio in Spain). He was jailed in the monastery with a tiny cell measuring only 10 feet by 6 feet with no changes of clothing, a diet of bread and water, and rarely any contact with anyone else in the monastery. After several months he escaped through a small window in the room next to cell, finally being free of captivity on August 15th, 1578.
After being nursed back to health he joined a meeting with reform supporters in October of 1578 and formally asked the Pope for their formal separation from the Carmelite Order. This group would eventually be known as the Discalced Carmelites, but it wouldn't know happen in 1580 while Saint John was serving as rector of Colegio de San Basilio in Andalusia. On June 22nd of 1580, Pope Gregory XIII signed the decree Pia Consideratione which formally authorized the older and newly reformed Carmelites. Saint John was elected as one of the Definitors of the community during the first General Chapter meeting on March 3 1581 and wrote a constitution for them. Over the next few years he travelled often, forming several monasteries (according to some reports he travelled over 25,000 km!). After an argument with Father Nicholas Doria who was serving as the Vicar General, he was sent to an isolated monastery in Andalusia named La Penuela. He fell ill quickly here and travelled to Ubeda for treatment, but died of erysipelas (Also known as Saint Anthony's fire, a bacterial skin disease) on December 14th, 1591.
Saint John of the Cross was beatified by Pope Clement X in 1675 and canonized by Pope Benedict XIII in 1726 with his feast day first appearing for November 24th in the General Roman Calendar of 1738. Pope Paul VI moved his feast day in 1969 to 14th of December, the day of his dies natalis (birthday to heaven).
Saint John of the Cross wrote several extremely popular books:
Dark night of the soul
Ascent of Mount Carmel
Spiritual Canticle of the Soul and the Bridegroom Christ
The Poems of Saint John of the Cross