St. John of the Cross, OCD (Spanish: Juan de la Cruz; 24 June 1542 – 14 December 1591), venerated as Saint John of the Cross, was a Spanish Catholic priest, mystic, and a Carmelite friar of converso origin. He is a major figure of the Counter-Reformation in Spain, and he is one of the thirty-seven Doctors of the Church.
John of the Cross is known 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”.