Saint Teresa of Ávila (28 March 1515 – 4 October 1582), was a prominent Spanish mystic, Roman Catholic saint, Carmelite nun, author during the Counter Reformation, and theologian of contemplative life through mental prayer. She was a reformer in the Carmelite Order of her time and the movement she initiated, later joined by Saint John of the Cross, eventually lead to the establishment of the Discalced Carmelites.