Saint John of Krst, also known as Saint John of the Cross, was a prominent Spanish mystic and poet born in 1542. He is best known for his role in the Carmelite Order, where he worked to reform the order and promote a more ascetic lifestyle. His writings focus on the spiritual journey and the union of the soul with God. He is celebrated for his profound poetry and spiritual treatises, including "Dark Night of the Soul." Saint John of Krst was canonized in 1726 and is recognized as a Doctor of the Church, highlighting his significant contributions to Christian mysticism and spirituality.